Because it isn't a mobile processor (it's your standard desktop cpu) it will guzzle your power faster so unless you have 2 batteries and are going to be near a powerpoint a lot a mobile variant is a better option. The standard processors are mainly for desktop replacement systems. The mobile processors conserve power by running at low and variable voltages. This is why they are a bit more expensive.
XGA stands for Extended Graphics Array, without getting to technical it basically sets out how 'big' your screen resolution can get, XGA is 1024, 768 pixels with a certain amount of colors (can't remember off my head).
WSXGA is widescreen XGA, so the 'array' is bigger again so you can have a larger resolution.
UXGA is ultra XGA, same thing as above. Might have more colors.
WSUXGA is widescreen ultra XGA.
LCD screens have a 'native' resolution. This is the maximum resolution they can have and it is also the default and 'best' looking resolution, other resolutions will give blurring, which is bad for text.. however you don't notice in low resolution games.
The drives that don't say 7200RPM are most likely 5400RPM or less. If you want to save money go for the non 7200RPM drive and you probably won't notice the difference. If you do a lot of network file sharing and multi-tasking, programming etc go for 7200RPM.
80gigs is nice, I wanted one but didn't come in 7200RPM.
My Laptop was a lil' over $3k.
It's not that heavy, but I think a 80gig drive would add a bit more weight to it for sure.. Mine is probably as heavy as I would go, can't remember the weight off hand I'll look for the order form and tell you later. Mine is the best I could come up with for mobility and power. It'll play Doom III for sure, but probably only on 10242x768 (although I'd use a 1.6 ratio res if I could because I'm on widescreen) which is still pretty good.
Works doesn't have Excel, it has Works Spreadsheet and it isn't as good. Works wordprocessor doesn't compare to Word either. And it doesn't have outlook or powerpoint, or anything similar. I haven't' used the works database yet but I'm sure it sucks in comparison to access.
You won't be able to fit a custom soundcard in. The motherboard they use probably doesn't even have a port for it. The integrated sound isn't that bad, it hardly compares to say an audigy but it works, I get no distortion from the speakers either.
Windows comes pre-installed. As does a lot of dell junk. Spend a few minutes uninstalling and disabling the usual windows xp services you don't need and you'll be crusing along.
I got the $20 USB mouse with my system, works pretty well ...