There are many players in the game of spyware removal. Most of them actually are just spyware themselves (don't click the popup saying you have spyware and someone can remove it for you).
There are many reputable and dependable programs out there that work very well to remove a lot of spyware. But part of the trouble is that one application typically doesn't do too well by itself. So Spybot works well. Ad-aware helps to clean up some more after that. And even Webroot's Spysweeper is a great app (though this one is a pay-for-removal) type which is annoying.
Lately I've been using a program called MalwareBytes Anti-Malware that so far seems to be working fabulously. We have been using it at work as well with great success. And thankfully, it is another free one. Updates are often and thorough. It offers a Quick Scan which works rather well to scan in about 10-15 minutes and remove a large bulk of the problems. There is also a Full Scan that can take anywhere from 30 minutes to 3 hours and scans a LOT deeper than the Quick version.
I can definitely recommend this program to remove spyware and malware from any computer. I have yet to find anything it really can't do. The best process I've found so far is to run a quick scan to get rid of most of the worst stuff and then once your system is more functional again, run a full scan to clean up the remnants. You won't be disappointed.
Of course, six months down the road, we may have a new king (RIP GiantAntispyware). But for now... this one is a must have.