Re size of screen: I don’t think it’s just the size of the screen, but rather the resolution you get can from it. No point having 15 inches if you’re stuck with 1024 x 728. Actually, my laptop screen (15″) has a better resolution than my new 17″ flatscreen monitor.

RAM buying aftermarket can save you 30-50%.

HD two year life span, great if user serviceable. If you are buying a macbook and need a bigger hard drive, check the aftermarket price. You might find (well at least in .Au) you can get a bigger hard drive cheaper than upgrading it. So the original HD can go in an external housing you bought with the savings.

Weight don’t forget to include the weight of the power supply and peripherals. A light laptop and heavy ps is no advantage over a heavier machine with a lighter ps when you need to carry both everywhere.

Memory Before Processor. – Look what type of RAM it takes and price it. Often it’s cheaper to buy with as little as possible and just upgrade yourself. Processors aren’t easy to upgrade (but possible on many laptops, provided it’s within the same series… which is pretty much pointless). RAM is an easy upgrade a novice can do.

Drives. – Be careful saying no to a DVD drive (if that’s even an option), since it can be an expensive “accessory” to add later on, especially if you wait and get it once it becomes harder to find. Make sure you really don’t need it. Also consider the need to reload the OS, make restore disks, etc. You don’t want to dig your own grave for a few bucks.

Hard Drive Capacity. – Get enough to last you about 2 years.max. After that, replace the drive with bigger/faster. 2 years of knocking around is asking for data loss. Put your old primary drive in a cheap usb enclosure and use it for backup. Now your growing, and being responsible and mitigating data loss (which means lost time/money).

Buy Online. – Call the manufacturer. Often they are willing to take a little off in hopes of getting the sale. Unless of course you have a “coupon code” that you can use online. If you happen to be employed by a big corp, or have a family member who is, they may have a corp discount available. Virtually all do with Apple and Dell. That’s a couple percent off right there. The call will never hurt (you can always hang up, and it’s an 800# anyway). Make it sound like your on the fence a little. May get lucky.

Built-In Wireless. – From the manufacturer is typically best. Some laptops are “wireless upgradeable.” An intel 3945ABG can be found rather cheap. $28. Doesn’t work for Thinkpad’s whose BIOS doesn’t allow non-Lenovo flashed cards to work (unless you use a utility to hack that).

Just my $0.02