Ok, I’m in need of some new Sci-Fi to read. Anyone care to give me some suggestions? I’m a big Star Trek fan (read: dork) and would like to expand my horizons. I especially enjoy books that deal a lot with non-human species, and enjoy the endless scientific detailing of Arthur C. Clarke…
Anyway, I guess I’ve outlined my tastes vaguely enough. Please suggest away 
Novus
Since other than Clarke and Star Trek (which suggests you might enjoy Jack Williamson’s “Legion of Space” books or James White’s “Hospital Station” books), might I suggest you take a look at this thread, which lists a bunch of important and good SF books (If you don’t want to wade through the whole thread, look towards the end of page 3)
Fenris
Pant Pant GAH!!! FLAHAIBAIIAIBIAIEALHGAHH
sorry, I was trying to restain myself.
Ender’s Game!!!
Oh, Alien species? heh. OK, read that, then read Speaker for the Dead. 
A new one I recently read dealing with aliens is Ringworld by Larry Niven. (ok, so it’s not new, but I read it recently, so there.) This story has the aliens you want with the Hard Sci-Fi of Clarke. I think it may be just what you’re looking for.
Partners in Necessity* by Sharon Lee and Steve Miller. Then Plan B and Pilot’s Choice, same authors. Although, I tend to forget sometimes that the Liadens are aliens.
David Brin’s Uplift series might be right up your alley (lotsa aliens, lotsa science). My brother likes them, anyway!
Also try any of the stories set in Larry Niven’s ‘Known Space’ future history. Ringworld would probably be the best start for a novel, but if you can find any of his collections of short stories that would probably be better - Tales of Known Space starts in the near future (actually our past, some of the stories of early exploration of the solar system are set in the 90s because they were written in the 60s) and go all the way to the 31st century. Lots of interesting and believable alien races, far-out technology, and real science.
This practically screams for The Star Diaries, by Stanislas Lem. It on the humorour side, very original and completly absurd, but you’ll laugh.
I really like Philip K. Dick, especially his stort stories. But then, I like science fiction in about the same way as I enjoy other fiction. That is to say, I’m not a big dork about it. More of a mainstream reader, I guess.
You might want to try something by Iain M. Banks, if you haven’t already. “Consider Phlebas”, “Use of Weapons”, “The Player of Games”, “Against a Dark Background”, and “Feersum Endjin” are his best efforts, IMO. Sweeping cosmic vistas, epic clashes between alien cultures, intelligent starships, wisecracking AI’s, and a certain behavioral complexity to the characters that is often missing from SF.
Yeah, Banks, that’s the ticket.
THANK YOU.
Finally, someone else is recommending Banks. I would, however, suggest caution before someone goes ahead and purchases his “Feersum Endjinn” – the phonetic spelling is laid on with a trowel, and has been done better by Russell Hoban in “Ridley Walker” – but otherwise, anything by Banks is good (including the non Sci-Fi published under his name without the initial).
“The Mote in God’s Eye”, by Niven & Pournelle, perhaps ?
“Endless scientific detailing” it has, and the engineer even speaks with a Scottish accent. Seriously, it’s one of the better ones around, IMHO. An intriguing alien, a fascinating aline society and two writers who certainly do not confuse infra-red with ultra-violet. Well, I like it.
S. Norman
Having spent a week (that I later regretted) wading through “Consider Phlebas”, I’d urge you to reconsider considering Phlebas. At best, Iain Banks’ material is rather dark and bleak. I was extremely disappointed with the end of Phlebas, and it turned me off reading any more of Banks’ works.