And, to give equal time to the ladies: There is quite a lot of lesbian fiction being published now by a handful of small lesfic presses -- Bella, Bold Strokes Books, Regal Crest, Bywater, Intaglio, etc. The vast majority of it is romance, romance-erotica, or romance with a fantasy/mystery/thriller subplot. If you're not into reading romance, then you really need to hunt and pick carefully.
In my (admittedly limited) experience, the Bold Strokes books are heavy on the gratuitous sex and quite predictable cookie-cutter romance; Bella books are largely romance and often have a lot of typos in them; Regal Crest books don't seem to get any structural edits so the books are often rambling or very overwritten. The Bywater books I've read have been quite good.
But overall I think I tend to go by author rather than publisher. Georgia Beers is probably (IMO) the best romance writer. I'm a fantasy/SF fan and I like strong characters and well-researched/designed settings with internal consistence, so the authors I look for are L-J Baker and Jane Fletcher. For comedy, I like Joan Opyr.
With major presses, it's harder to find lesbian fantasy. Manda Scott's Boudica (sp?) trilogy (or maybe tetrology? can't remember) has gay, lesbian, and bi characters, and is excellent. Mary Gentle's "The Golden Witchbreed" is also very good and features lesbian characters. Joanna Russ's "The Female Man" is SF that has about a zillion layers to it, so while it's not a 'fun, easy' read it's very thought provoking, and was about a century ahead of its time. Jay Lake's "Green" features a lesbian/bi protagonist and a really well-drawn setting. Nicola Griffith's older SF novels are all lesbian-focused and very good, and her more recent thrillers (the series featuring the lesbian character Aud) are superb. Well, actually anything Griffith writes is superb. I'd happily read her laundry list.