I bought a Fujitsu-Siemens Amilo L1310 from dabs. Quite a good price, nice laptop. When I got it the battery was fully charged - they're supposed to come flat. The Windows validation was playing up as well. I think this 'new' PC had been sold before. dabs agreed to take it back for a full refund. Wonder who'll get it next...
I have just ordered a Dell, which I hope will be newer than the Fujitsu. Dell give you a lot of control over the spec of the laptop - CPU, HDD, RAM, Graphics, XP Home or Pro - all selectable. Prices aren't bad in my opinion. Customer service... hope I don't have to find out!
When you talk about power, do you want a games machine? If so, you need to get one with an 'off board' graphics card. The downside will usually be a poor battery life.