SXGA (Super XGA)
A Display Standard referring to a video adapter capable of a resolution of up to 1280 by 1024 pixels.
SXGA+ (Super XGA+)
A Display Standard referring to a video adapter capable of a resolution of up to 1400 by 1050 pixels.
WUXGA (Wide UXGA)
A Display Standard referring to a video adapter capable of a resolution of up to 1920 by 1200 pixels.
Generally speaking, the more resolution the better. On notebooks, the drivers typically skip the analog conversion so you end up with a digital connection creating a crisper picture ... in desktops, this is referred to as a DVI connection, typically only available with the more expensive LCD monitors; cheaper ones don't offer that.
As a practical matter, most people can't read a display set to anything other than 800x600 or 1024 x 768. Better than that and you need a magnifying glass or you're a kid with zoom vision or you're using a 19" or bigger external montitor; not a notebook display. With the better resolution you are ususally getting other things, such as a better graphics card, superior viewing angles, etc.
Similarly, the better notebooks have better LCDs which permit wider viewing angles both vertically and horizontally. If you always look from one angle, this isn't a big deal. If you share watching movies, say on an airplane with your kid or spouse, this is super important.
Personally, I can't stand cheap LCD displays. On the other hand, with notebooks, everything is expensive because of size and you are very limited in future upgrades. In a sense you are stuck in three positions: buy a low end one that is pretty good and plan on trading up in a couple years; buy a mid-range one and hope for the best or buy a super one and stretch it out.
I've always bought the best and stretched it out with relatively good success. The first one (a color Compaq) cost about $7k, the next about $5k, the next about $4k and then I was playing around with the idea of a 17 inch Apple - about $5k or Dell about $4k and recently found out about the Sager which would be about $3k for a better unit. Each one has lasted a good 3 or 4 years and the displays are always awesome for the period.
Even now my 15 inch Dell 7000 (the first of its era) looks great, but the 333 Mhz is just getting slow on the boot ups and I'd like a bigger display. But it's lasted a good 4 years. Had I purchased a smaller, cheaper display, I'd have had to trash this system two years ago.
Hope that helps.