what laptop should i buy?

my current laptop has 1G of ram and runs at 1.4 GHz with windows XP. It has trouble keeping up when editing video or running multiple programs. I've been looking at machines with 2G or ram and a core 2 duo processor and runs Vista. since Vista requires much more power than XP, i'm not sure how much performance gain I'll actually get with this upgrade. Anyone running vista with similar specs to what I'm looking at? does it run well or should I think about spending more money for a higher end laptop? thanks