A little real world advice here. Mega Pixels are a selling feature. 5 has to be better than 3 right? Far be it from Zurg to suggest that bigger isn't always better, but you should consider what you picture taking needs are. Say, like Zurg, you have a shoe fetish and take pictures of funky feet for your web page.
For most web stuff, 640 x 480 is fine. Say you are Mrs. Zurg and like to hang a lot of 8 by 10 blow ups of the little Buzzes running around on vacation. You will need enough pixels to make a nice big print. How many Pixels? Here is an estimate of the minimums to get a good print I got from Ofoto (Kodak):
Print Size ---- Minimum (Pixels) Needed --- Mega Pixels
4x6 ------------------ 640x480 ----------------- .3
5x7 ------------------ 1024x768 ---------------- .8
8x10 -----------------1536x1024 ---------------1.6
11x14 --------------- 1600x1200 -------------- 1.9