I’ve been using CiteULike more and more to track my references, but up until now I’ve still been maintaining a separate bibtex file that I edit by hand. I’ve decided that having pretty spacing in my file is not worth the extra effort compared to:
wget http://www.citeulike.org/bibtex/user/rpadams -O rpadams.bib
Anyway, CiteULike is highly recommended.