This horse is nearly flogged to death already, but I'd like to take a a moment to make clear *why* the difference between 6MP and 7MP is not really noticable:
megapixel count is a square measure - the total number of pixels on a rectangular chip. However, resolution, the best measure of how detailed something looks, is a linear measure (dots per inch). To make something look twice as sharp, you need four times as many megapixels. Conversely, the difference between 6MP and 7MP, while it sounds like a 17% increase, only gives you an 8% increase in resolution.
As a rule, you need to change resolution by at least 50% to make a perceptible difference. In other words, if you're not getting at least double the pixel count, save your money.
An 8% wider frame buys you an almost imperceptibly larger margin for cropping your mis-framed shots, that's about it. Probably not worth 25% of the cost of a brand-new p&S camera - you should spend the money on memory, batteries, etc.
The other thing to think about is how you'll use the photos.
For display on a computer screen (100 or so dpi or x about 1 foot wide) 2 megapixels will be more than enough, and 4 is just about future-proof.
For viewing over the Web, pity the poor slobs with modems. And even with a good connection, anything over a megabyte in storage size (ie, 2 to 4 megapixels at very high JPG quality) starts to have a perceptible delay. Your photos better be damn interesting if you expect people to wait around to view them - and remember they can't actually see the difference on their computer screens beyond about 2 mp.
For printing, consider that professional printer output is typically 300dpi or better, but you can reliably get great results from an image resolution of 200dpi or lower [modern photo printers will interpolate -fill in- the missing pixels in a way that keeps your print from looking pixellated even under close inspection].
So how many pixels do you need to make a higher-resolution-than-you're-likely-to-notice (200dpi) print ?
3x4: 0.5 MP
6 x 8: 1.9 MP
12 x 16: 7.7 MP
24 x 32: 30.7 MP (time for medium-format film, or a $40,000 digital camera)
Standard letter page: 8.5 x 11 : crop from 9 x 12: 4.3 MP
In short, for anything you print or show at home, 4 MP will be ample. If you want to sell posters, you need big film (or a big inheritance).
If you really think it'd be cool to make a print that's just a few centimeters wider than you otherwise could, you'll be tempted to go for 6-8 MP, but as explained in my first three paragraphs, the returns diminish rapidly.
And yes, I ordered my new camera and my new computer together - my old computer just would be too slow to process my bulky new images.