You just want to take this on vacation, and then what? Are you replacing the desktop with it? Unless you require the portability for some reason, I wouldn't recommend having a laptop as your primary system, you'll never get the same price/performance ratios you can get with a desktop, and laptops rarely last as long. They run much hotter, and heat is death to electronic components. You won't have much choice for the OS, it'll be Windows7 (don't even think about Vista), other software should just be whatever you're accustomed to having on your desktop system. For components like RAM and disk space, get as much as you can within your budget, certainly no less than 3 Gb of RAM and a 150 Gb disk drive. From what I've seen AMD processors run quite a bit hotter than equivalent Intel processors, so I'd avoid them.
I and people I know well have had good success with Toshiba, HP, and Acer laptops, I specifically wouldn't recommend Dell. Dell's laptops generally cost less for what look like the same specs as others, but it's a little deceptive. Dell tends to cheap out a bit on some of the more subtle things, like cache and bus speeds and video RAM, to keep the price down, and the result is poor performance. You may feel that's not an issue if you're not gaming, and it may not be for your particular requirements, but if you do anything more demanding than word processing, simple spreadsheets, Internet, and email, you may be very unhappy. Photo and video editing, for instance, are pretty demanding, you don't want to be waiting 2 minutes for Photoshop, or whatever you use for such things, to run a simple filter over one of your digital photos.
You'll also find that any machine purchased off the shelf these days will have a lot of useless software installed by the manufacturer, some of it a bit invasive. The last HP laptop I acquired, for instance, had about a dozen such things on it, for photo editing, photo album management, silly little games, online gaming software specific to HP's online gaming site, proprietary updaters for all of it, monitoring software that reports back to HP about the state of the machine, ostensibly to warn you of signs of potential failure, and some damn fool thing called the Customer Experience Improvement package, which also reported to HP what the machine was being used for. And I found a task set up in the scheduler to activate 12 months after the initial activation of the system to pop up and offer me an extended warranty. I spent about two hours tracking all that crap down and uninstalling or deactivating it.