not sure how i went this long without spotting this thread, but oh well...
most of what i do rarely involves fast mixing that would typically be associated with VJing, but i do background video loopy stuff at large youth conferences & concerts a few times a year. every now & then there's a snooty fundraising gig for rich peeps (yawn). the most recent one was "The Gathering" -
http://www.gather4him.net/ - got to toss up video stuff on 2 screens behind David Crowder Band and some other peeps - woot!
if you're windows-based, and don't mind investing some time into learning a (fairly huge) program, definitely check out Visual Jockey:
http://www.visualjockey.com/i've been using it off & on for several years, and it's been very flexible & pretty darn stable for all i use it for. best of all, the newest version is FREE!
most of the bigger events involve multiple projectors & screens, so i often run stuff off of my PC, then thru a Matrox external box (the Triple Head2Go, or at this last gig, the Dual Head2Go), then out to the multiple projectors... i love using Visual Jockey (vJo) for this, because it's really flexible with stretching out smaller clips to span the entire width (2048x768 or 2400x600--i drop down to 3x800x600 for the triple-wide stuff) of the screens. but with vJo you can also setup comps that just tile multiple clips across, or that are the full res of your screens, whatever. one BIG downside with the program is that it doesn't have a content management system. anytime you want to just drop a video clip in there for playback, you have to build a composition & save it out. so... with much flexibility comes much prep-work.
i almost always have a backup system in place for those multi-screen events. didn't have a single crash at the last event, but the high-res stuff really does put your PC thru the ringer. the backup system is essentially what i use when VJing smaller shows or parties... it's an Edirol V4 mixer with several DVD players running into it (with event logo loops & a bunch of other stuff burnt to DVDs).
yeah... i've rambled on a bit too long.