Vic, yes for web delivery I reckon FLV's caught up with everything else now other than maybe stuff like the DivX movies on Stage6.com
I used Adobe Flash successfully with the On2 codec selected (as opposed to Sorenson). Nice result.
Also used On2 Flix Standard successfully and could not really tell the difference from the 2-pass VBR Pro trial version's result.
The last one I just let Brightcove's Publishpod do it for me with all the best settings inc 2-pass and the result was great. But obviously then Brightcove will be hosting the file for you.
It certainly has the largest installed user base, and it's pretty platform agnostic. So, for the purposes of getting it out to a lot of people with a minimum of fuss, yes, FLV's the best.
I use the FLV converter built in to After Effects 6.0. Very nice output, but unfortunately, it doesn't do batch.
I sure hope Vegas 8 ships with the On2 codec, so it can do FLV natively.
I render to AVI (generally DV) from Vegas and use Riva FLV Encoder. Though I do now have access to a "real" (aka, commercial) FLV encoder, so I may try using that. I've been pretty happy with Riva, though.