Just for file transfers, I really like SuperBeam. It does just one thing, it's really fast (the WiFi direct connection is fantastic) and the PC software is just a file that you run, no installation or other crap necessary.
I'll check it out, thanks! AirDroid is a first good-enough solution I discovered, but it has way more features than I need - you can tweak and manage your mobile device from the web browser in all kind of ways, but the only thing I use is downloading/uploading files.
