Well, you like Pratchett, so that's a start.
What are you interested in? Are you interested in swords & sorcery, fantasy in a modern setting, what?
I liked a lot of what Modessit did in his Recluse series, and I thought that his Ghosts series was interesting, too. Both of them are a bit different than standard fantasy fare in terms of what's going on, and he's big on doing more complex social stuff than just kings and emperors. If you don't like his style, though, you'll hate the series -- and some people really don't like his writing style.
George R.R. Martin is currently hugely popular, and I'm lovin' him along with everybody else. I tend to be skeptical of a lot of existing series, though, because I've been burned by series that spiral out of control. Martin has been clear from the get-go that this is a six-book series... maybe it actually will be.
Robin Hobb's Assassin trilogy was a lot of fun for me -- a nice system of magic and a good voice. When it was over, I was just about ready for a story that wasn't told from the point of view of an unhappy young adult, but at the time, I was very very into it. A lot of people had issues with the NEXT trilogy (the Liveship Traders), but I personally liked it a lot, too -- more about magic and politics and less about swords, though. Her third series, which is about the protagonist from the Assassin series as an adult now and dealing with a lot of people who are acting the way he acted as a teenager, has been great so far.
I just recently read the first book of an incomplete series by Jude Fisher -- Sorcery Rising. A lot of interesting political stuff, and the fight scenes were handled very well. Not a "quest" type story at all, but rather a bunch of infighting and wrangling at a giant trading faire that happens every few years. I had a really good time reading that one -- my only complaint was that some of the POV stuff was weird -- we seemed to move from one person's head to another in the middle of a scene. Once I got used to it, it didn't bother me, but it's a bit different. (Note: It's not omniscient viewpoint, it's third-person-limited viewpoint that changes in midscene to third-person-limited in someone else's head, near as I can tell.)
Those are all just my personal opinions, obviously. Some people will likely chime in and hate some of those, and others will have suggestions that I haven't read (or didn't like much myself).
And hey, failing that, shoot me an e-mail and you can read one of my currently unpublished masterpieces.
