I was curious on the tablets myself. But I couldn't afford the wacom's, even if I could. I wouldn't want to shell out the dough to buy something that was going to collect dust 6 months later.
So I went the inexpensive route and got a Aiptek Hyperpen 6000U. For 40 bucks it gave me a feel for a tablet. And was happy with what I got. Altough it's quite limited on the active area 4.5" x 6", and only 512 levels of pressure. I still had a fun with it, worked nicely with Photoshop. Check their site out.
www.aiptek.com.
But I'm sure wacom, will blow aiptek out of the water. I'm sure someone here will have good advice on the wacoms. The only thing I will recommend is buy the biggest size you can afford.