When I finished reading Anne Stuart's The Wicked House of Rohan and Ruthless, it occurred to me that she is one of a very select group of authors I've continued reading since discovering the joys of romance novels in 1993. Of the select group of others, most fell by the wayside immediately or almost immediately. I read 23 books by 13 authors the first year I read romance, and Anne Stuart is the only one I continue to follow oh-so-closely. I don't read all of her romantic suspense, but have read every one of her Ice books and nearly all of her historicals (and have TBR some of her very old category titles). Lisa Kleypas and Teresa Medeiros are nearly auto-buys, but much less read.
Rather than going year by year, let me list my most frequent romance DIK authors (from most to fewest multiple DIKs), whether or not I continue to buy and/or read them, and if not, how long they lasted. It's not a tremendously large list, so it shouldn't take that long.
Nora Roberts/J.D. Robb, with 11 DIKs, the 11th added just last year with 2009's Promises in Death: I discovered Roberts in 1997 but didn't read her as J.D. Robb until 2006. I continue to read her as the latter, not so much the former.
Julie Garwood, with 9 DIKs: I read Garwood's 1993-published Castles in 1994, beginning a string of DIK reads. Sorry to say, but I gave her up when she moved into romantic suspense in 2000. She wrote another historical a couple of years ago, and though I bought it, it remains unread.
Catherine Coulter, with 5 DIKs: Coulter was among the thirteen authors I read in 1993. While her quality varied from terrific to horrendous - and some sub-genres went off-limits quickly - I continued to read her Regency-set historicals long after most, stopping after Pendragon, with 25 books by her under my belt..
Kathryn Lynn Davis and Anne Stuart, both with 3 DIKs: If Kathryn Lynn Davis hadn't stopped publishing with Somewhere Lies the Moon, no doubt I'd have continued to read her. As for Stuart, she continues to amaze me.
Connie Brockway, Christina Dodd, Jillian Hunter, Mary Alice Monroe, Julia Quinn, Deborah Simmons, and Katherine Sutcliffe, all with 2 DIKs: I have several of Brockway's books TBR and will probably buy her again. As for Dodd, I continued to read her long after she and her closest attacked my integrity, and that of AAR, but at some point I realized I could no longer give any author business if she actively tried to destroy my website. Eventually that extended to Julia Quinn, whose behavior was more subversive. She was the only author contacted in 2007 to participate in AAR's 10th anniversary who refused, and unless she hears of this, she probably has no idea that I know why. (Hey, as a private citizen, I'm no longer obligated to take the high road.)
I continue to buy and read Jillian Hunter, even though it's been two years since reading Wicked as Sin, which I thought was only slightly better than average. I only fell in love with Mary Alice Monroe in 2002, and until last year's Last Light Over Carolina, she'd consistently blown me away. I look forward to her next book.
Deborah Simmons only recently returned to publishing after a hiatus, and I continue to buy her books, though it's been a while since I've read one. Finally...Katherine Sutcliffe, who stopped publishing in 2005. I stopped reading her after My Only Love, which I liked, mainly because her books' premises stopped interesting me and I knew she was capable of some real clinkers. Then too, she became the poster child for Bad Author Behavior. I felt she was misunderstood and tried to help her navigate what was at the time uncharted territory, and it exhausted me.
What other authors have been published for a very long time whom I continue to read today? The first who comes to mind is Mary Balogh. I didn't "get" Balogh until 2001, but my favorite book by her to date was just published this summer: A Secret Affair. She's been published since 1985, so...wow. Linda Howard is another long-published author to have thrilled me fairly recently - with her Blair Mallory books. Though I only first read her in 1999, she was first published in 1982, so again...wow.
Other authors published way back when whom I read for quite a while, even if none of their books ever earned DIK status: Let's start with Loretta Chase, whose 1995 "classic," Lord of Scoundrels I only first read in 2006. More than a decade after publishing LOS, she published Your Scandalous Ways, which I truly enjoyed, and I happily look forward to reading both back-list and subsequent releases as time permits. Chase's first book, btw, was published in 1987. Next up: Patricia Oliver, who died several years ago. She's the only Trad Regency author I "got" for many years, and deserves mention simply for that reason. Also, Lorraine Heath and Leanne Banks - both of whom I continue to buy if only rarely read - and Elizabeth Lowell, Ruth Langan, and Jill Barnett, all for whom I have multiple books TBR, even though I stopped buying them some time ago.
I'm sure I've left out many authors I'll later wish I'd included, buts it's time for the flip side, and a few long-time authors I eventually gave up on. Obviously there are many, many, oh-so many I can't possibly list them all, but these three came to mind for three different reasons, so I'm listing them: JAK/Amanda Quick, Marilyn Pappano, and Elizabeth Bevarly. I read many books by each of these authors, and gave up on Krentz/Quick when she eventually became derivative of heself. As for Pappano, while I have many from her backlist, and even am a fan of books following Season for Miracles in her Bethlehem series, once I subsequently read SFM, I was turned off so strongly that I never bought another of her books. With Bevarly the reasons are many, and not all are book-related. Apparently I do hold a grudge. 'Nuff said.
After writing all this, it amazes me that Anne Stuart, Mary Balogh, and J.D. Robb continue to thrill after so many years in print. I look forward to additional greatness from them, others on my list, such as Loretta Chase, Linda Howard, Lisa Kleypas, and Terersa Medeiros, and still others - from Madeline Hunter (whose first book came out a full decade ago!), to Elizabeth Hoyt to Rhyannon Byrd to Cherise Sinclair - whose careers are not yet as long-lived. And if Sinclair's name comes out of thin air, know that I rarely write about the erotic romance I read, although that will likely change in the very near future.
Still Reading After All These Years
Lewis is a long-time fly fisherman and quite comfortable expressing his emotions—which no doubt accounts for the love so many of his patients expressed for him when he was their pediatrician—so one of the recommendations was for Mary Alice Monroe's Time is a River.
The night started out strong; I hand-sold from my register a copy of Lisa Kleypas' Then Came You almost immediately to a woman who'd never read the author's earlier work. I noticed that of the 48 copies of Changeless, ten had already been sold. Though I did sell two more, we lost two double sales to customers who would have tried Changeless if they could also have bought Soulless. Needles to say, I short-listed several additional copies of Soulless. 
As for recommendations, I made one couple pretty happy (I'm not quite sure what it was they bought that tipped me off) when I mentioned the up-coming reissue of a few of Mary Alice Monroe's best. As I talked to them about her, the husband realized his wife had loved The Beach House (sweet, right?), so when I handed them a slip of paper with Sweetgrass, Swimming Lessons, and Time Is a River hand-written on it, I knew I'd made a future sale. I also know that the next time another couple returns, they will take a strong look at Christopher Moore's A Dirty Job and Lamb (another hand-written slip of paper)...
it's not a huge leap from Spencer Quinn's Dog Gone It to Moore's absurdist humor. I hope my Sandman Slim recommendation (the mass market release for Richard Kadrey's book comes out late this month) does the same magic for the guy who bought some Jim Butcher...he seemed intrigued and appreciative with his hand-written slip of paper.