Macs are pretty good options in IMO. If you dont want to deal with viruses or tweaking/upgrading and just want something to surf/pictures/videos it works very well. The only real downside is its a bit more than a comparable PC and upgrading is expensive, but you get to be cool like the mac commericals say.
PC-wise, I would say IBMs, Sony, HP and Toshibas are good bets to be good brands. Out of the those, HP would be the best bang/buck.
Here are the things I would recommend in looking for:
Least -> Worst
Intel Core2Duo (Conroe)
Intel Core Duo (Merom)
AMD Turion X2
Intel Core Solo
Pentium M
AMD Turion
AMD Sempron
Intel Celeron
To tell the two Intel Core Duo's apart, look at the product number. If its the T2xxx its the old core. If its T5xxx or T7xxx its the newer and better core. Note: Not too much difference between the two cores except the newer runs a tad cooler and faster. However, if you do a lot f CAD, gaming or anything CPU intensive, the later core will be significantly faster.
Next thing is RAM. 1GB is minimum, especially if youre thinking about Vista. Vista wont even boot with 512mb and shared VGA ram. 2GB is where it is happy.
Lastly the hard drive. Faster RPM = faster loading/boot/etc... Also the more the merrier.
The other things to consider is what do you want it do. That will dictate the screen size and extra features. 15.4 LCD widescreen is standard and dvd burners should be considered and feature on most standard notebooks. Theres also extra video Outputs like S-video or even DVI.
Pricing wise its usually the smaller and more portable its more expensive. Also the larger and more powerful it gets more expensive.