well, the 7D boasts an 18MP sensor, meaning that it is capable of capturing detail that, down to the pixel level, resolve "properly".
However, it's obvious from the comments here that many people are quite satisfied with say a 1MP Web image or, at most, say a 7.2 MP 8x10 print (300ppi). Or a larger print, as long as you keep your distance!
And that's fine, no criticism of such folks and, in fact, a lot of things that I shoot just don't have "tack sharp" demands -- if I can get a "good" focus at say a sports shoot or some kind of event, or street photography, I'm good -- I may do a quick check at some magnification, but again "tack sharp" is not a core requirement, especially for a lot of the handheld shooting I do.
But, there are considerations for approaching things another way when it matters!
For example, for a lot of my wildlife shooting, I routinely have to crop pretty closely, and yeah, even to post a pic like that on the Web, or to print a 5x7/4x6 or certainly an 8x10, sharpness at the finer level does matter, otherwise you flat-out lose detail!
I don't have a 7D, but if I did, for much of my shooting I'll use gear and techniques to maximize/optimize sharpness, because for that type of thing sharpness does matter! And so if you are using techniques and gear for maximum sharpness then you shouldn't feel bad about examining your images closely to ensure that your technique and gear are working for you...so that, like I mentioned earlier, you are shooting with 18 usable megapixels instead of 7 or 10 or whatever!
There is also the fact that in stock and publishing outfits, images are often routinely examined at 100% for not just sharpness but also for lack of image noise. You may say "I'll never shoot for that stuff", but eventually, you may actually capture some shots where you say "Wow! I wonder if I can sell that or get it published?", and then, looking a bit more closely, you recall this and other "anti-pixel-peeping" threads, and never bothered to hone your skills to produce those "tack sharp" images...