The thing with demo versions is the fucking retarded crippledness some companies go with. Some offer a complete uncrippled trial though, and that's way more fair if you ask me. In what state of mind do you expect me to buy a plugin which I can't test fully out? But for those who add like random beeps and shits every 30 seconds... oh my god, it drives you nuts when you are trying to concentrate on what's really going on.
As for the rest of the post, THUMBS UP! I did the same thing a while back, and now I'm only running freeware plugins except for ApTrigga (which I will buy soon... it's cheap as dirt). One thing you've got to be careful with though, is the quality of the freeware plugins. Some of them love to crash your DAW and stuff, but some are REALLY good. I think GVST is one of the few free plugin suites that offer quality plugins with 100% stability. Never had any of those plugs crash on me. There is an awesome compressor named Density mkII too, but I've had that one crash REAPER. I was running Density mkII 1.0 though, and there is a 1.2 out now so maybe it's better..
You will also be a better engineer by going legit, as Lasse pointed out. Back when I was running a gazillion plugins, I had absolutely no clue of what to use where, let alone how to use them. Now I only have what I need, and I keep learning something about them every day. And it feels awesome when you finish a project and you know you did it the legit way =)