Software for handling camera RAW-files
I haven't used it myself, but I have read good things about dcraw from time to time. There is apparently some sort of drag-drop windows frontend, no clue how well it works.
Note: I can't seem to reach the dcraw site right now, don't know if that is temporary or not...
After doing it for a few years, I personally stopped shooting RAW last year. Since I am usually rather thorough while shooting it didn't really give me much apart from larger files requiring more storage.
Considering you mention Apple Aperture, I will assume you mean your question for Mac software, but I'll answer with the programs I've been using previously and currently on Windows for the same.
I have a Canon EOS 20D, if that matters.
Previously I used Capture One by Phase One. It was nice, but was basically just a conversion tool. Until I upgraded to one of the higher licenses, it had a very small queue and was rather cumbersome. It did produce very good quality images however. In lieu of your question about easy to use software, I would not recommend this. It supports both Windows and Mac.
After that I tested Bibble, which also supports both Windows and Mac. It too leans heavily towards conversion only. Personally I liked Bibble a lot more than Capture One. The price was nicer as well, at $159 for the Pro license.
I've also tested Adobe Camera Raw, in conjunction with Adobe Photoshop Elements and Adobe Photoshop Album. Worked rather nice, the conversion process felt a bit clunky to me though.
I believe Picasa supports the RAW files by my Canon camera, but I have never tested it.
Currently I use Adobe Photoshop Lightroom 2, which serves me very well. The price wasn't all that bad, but yes, it's slightly more than what you might be used to for "home" edition type software. Then again, camera RAW files are slightly above what I would suggest "home" people do anyway.
If anything, I would suggest to people I know that ask to go with Lightroom. It has the organization tools built in and the conversion tools are both powerful and, compared to others I've tried, relatively easy to use.
Picasa handles the RAW images from my Pentax without any problems, on both windows and linux.