You might want to check out http://appdb.winehq.org/
- for any mass market commercial software there should be an entry that lets you know how well it runs in wine. I would also second EDDY1's suggestion that a lot of software you have in windows, you might be able to find a good open source alternative for. If you're worried about being able to open old files, it's worth noting often open source programs have better support for legacy file formats than newer closed source programs.
If you have custom programs you need to run, you'll just have to try them out in wine, but there's good odds you can make them work.