The Wacom tablets are quite literally awesome. I started with a bamboo and moved onto a intuos 4 medium, the main difference other than the obvious price is the quality. Don't get me wrong the bamboo is good but once you've tried the intuos you won't ever go back. The pen on the intuos feels a lot more responsive and sturdy compared to the bamboo.
Your budget wont stretch to an intuos so i would say go for the bamboo. They come in 2 flavours, the bamboo pen and the bamboo pen and touch, the main difference is that the latter comes with a mouse and if you don't need a new mouse save yourself £25! Teh bamboo comes with drivers that allow you to customise the various buttons on the tablet and the pen. The intuos allows you more customisation, especially the levels of pressure on the pen.
All in all you can't really fail with any of the Wacom range, they really are the best on the market IMO. If you want anymore advice just PM me.
Oh and they'll take a bit of getting used to after years of using a mouse but once you get used to it you'll never go back to a mouse for editing, it just feels much more natural to use the pen for that kind of work.