I use a Boss/Roland BR 1100 for practising...it's got an amazing drum machine on it, as well as a 40 gig harddrive that can record your inputs.
It's also got a fantastic mastering tool kit on it, and the full COSM effects pack on it. The whole thing cost me around 400 GBP whe n I bought it in 2005, and is probably the best money I've spent on accessories.
Comes fully reccommended!