The video card is arguably the most important, most expensive, and most personalized component in your machine. Every other computer part is now basically a commodity that isn't too expensive individually and doesn't make much difference what you get as long as you buy in the "best value" range because the performance between low end and high end doesn't really make a noticeable difference. Video cards on the other hand vary widely in their performance and you basically get what you pay for. Fortunately is is also the easiest part to change out and upgrade. This is good because most computers used for gaming can get an extra boost of life by just upgrading the video card.
The latest intel chips have a basic video card built in, so if you are only doing websurfing, you shouldn't get a separate card at all. If you are going to be playing any games, you will need one for sure. Which one?
If you are planning to install a Hackintosh, getting a mid range latest generation Nvidia card is going to be the best decision for you since it is easiest to run with.
If you want to compare and contrast options, search TomsHardware.com for "Best Graphics Cards For The Money". They run regular reviews of what is recommended for cards.
Based on my research, this is currently the video card I recommend for the average computer builder based on performance/cost, sound levels, heat dissapation, energy use, etc.