I love each for different reasons.
Star Wars is just THE best space-opera (and here I am talking ONLY of the first trilogy, the second trilogy was a travesty and Lucas should be ashamed of himself). Star Wars has the benefit of a world that is not exactly pristine. I love the moral ambiguity around Darth Vader and that the Dark Side of the Force isn't necessarily *evil*--more misguided and blind to consequence but not evil in the simplistic sense you normally see in Hollywood films.
Star Trek, on the other hand, gave us a very pretty future--no greed, the only violence came from outside the Federation, etc. Of the two, Star Trek seems the more *achievable* future since, strictly speaking, all of the tech in Star Trek is theoretically possible (yes, even the transporter and the warp drive).
That said, I think that Star Wars had better aliens. Some of the aliens in Star Wars are *actually* alien while the Star Trek aliens weren't really alien. One thing I'd really like to see is a portrayal of aliens that are truly Other. I understand that, up until very recently, aliens had to be people in suits or makeup. Now with CGI we can start seeing truly *alien* aliens instead of bilaterally symmetrical aliens. Imagine, if you will, an alien built on a cephalopod (octopus or squid) body and you start to get an idea of what it is I'm hoping to see in future sci-fi.
Cheers
Aj
ps. may the mass*acceleration be with you.