Personally, I very much prefer to hear the 
original voices, so I'm generally against dubs -- 
I'm not sure if it's just me, but I find the 
general speech of Japanese voice actresses much 
more relaxing than any other language.

As for the cost issue that I mentioned in my 
title, obviously the cost of getting digital 
fansubs is much less than waiting until a company 
has licensed the show and released it in the US 
(and therefore, also much faster -- sometimes the 
lag between air dates and subbing is less than 2-
3 weeks).  The big savings, though, is when I go 
to buy cels -- although this seems to be less the 
case lately, it seems like cels for new, 
undiscovered shows are usually quite a bit 
cheaper than those that have had an American 
release.  That window of time gives the 
opportunity to buy up good cels while they're 
still cheap!

However, I will say that getting bilingual DVD's 
once they're released in the US (months later) is 
great, since the quality is usually a little 
better and it's easier to take screencaps when 
you switch over to the dub.  The only technical 
issue I have with most US DVD releases is that 
while they'll advertise Dolby 5.1 audio, it's 
only available on the dubbed track, and not on 
the sub.