rear wheel bearings... do it myself?

[intellibomb]

hi everyone in cyberspace


so here is my dillemma:
my driver rear wheel bearing is toast. i was driving and all the sudden a horrific grinding and then then it sort of popped, and then it was a steady, lower pitched squeally grind.
i was like 100 miles from home at this point, and i just kept on trucking cuz i had no choice. i get home (slowly but surely) and i examine the wheel in question and there is metal shavings all over the rim and the wheel (when i did the ol' tire kick) looked as if it were about to fall off.

my question is:
can i just replace the entire hub assembly off of my parts car?
or, conversely, would i be better off just replacing the wheel bearing on the working car with a new piece (cost and time wise)?

also, do the new bearings need to be packed with grease? i have heard conflicting reports: my local dealer says that "the bearings are sealed and come with lubricant from the manufacturer", but another mechanic and reports on this site have told me they must be packed with grease or else they will just fail again.

i was quote $95 for the bearing, $14 for the seal, and $300 for the labor at the dealer.
the private mechanic said $280 for the labor, plus $50 for a machine shop to pack the bearings....

what should i do? i would much prefer to just replace the entire hub if possible and practical (much cheaper and i can do it myself).

thank you so much for any input you all might have on my plight

thanks
JJ