Couple of points...
Sneak is actually very easy to raise. Go stand near someone and sneak. Check to see if you can be successful at it (you'll need at least -some- sneak skill) and that you're in a position where it will increase (check the progress bar on the skill).
Then get a paperweight, weigh down the control key, and read a book for a few hours.
Second, some guilds actually do have nice rewards for climbing to the top: Mages, Tribune Temple, Morag Tong. Legion, Thieves and Imperial Temple (I think) offer some rewards as well, though not as good as the others.