I wouldn't go with an AMD on a laptop for sure because I can tell you that I made that mistake already. It's not that it's bad, it's just it's not what I want when I'm loading multiple applications. Though this may not be what you think is you, you'd be surprised how much processor power you will want to use with your laptop.
and if you can splurge for it
Lenovo is a fantastic brand, one of the better ones imo. The latter comes with a downgrade to XP, which will really help you improve multitasking tasks and is a real bargain at that price. If you do want Vista, then either will work just fine but as a computer sales rep, I can tell you that Core 2 Duo makes all the difference in a work horse computer.
This is also a good deal:
Comes with Microsoft Office already installed. Is also upgradeable to 8 GB of RAM, which is great for extended use (3+ years).