If you can afford the sticker shock - stick with the Core 2 duo's T7000 and higher. They've included some nice chipset improvements to memory management and cache pipelining which make it worthwhile IMO.

Of course - they're the premium chip to get these days, so this might blow out your budget.

Also - there actually are some RAID-0 and/or Raid-1 configured laptops, which would help with performance or reliability (depending on what your primary concern is). I'd go performance, so Raid-0 on 7200RPM's, but that's just me:).

Of course - I get into the "if I am going to spend THAT much - I might as well tweak it all of the way out....".

All right - back to my Hardware Junkies anonymous meeting.....