My brother's name is Gus and when we were in Austria, people constantly called him Goose, like a long U sound. So now, to pay him out, we call him Goose. So yeah, that's another pronunciation. :)
This is the name of the title character in the poem 'Gus the Theatre Cat' by T. S. Eliot in his book 'Old Possum's Book of Practical Cats.' Gus, who's real name is Asparagus, is also a principal character in Andrew Lloyd Webber's award-winning stage musical 'Cats.' In the original West End production, the character was portrayed by Peerapat Yensudchai. When the show transfered to Broadway, the character was portrayed by Stephen Hanan, who won a Tony Award for the role. In the filmed 1998 version, he was portrayed by John Mills.
It's a tad old-fashioned, but not in a bad way. The name is short and simple, and not too boyish either. It's not the greatest name out there, but it's not bad either. It makes me think about Gus Gus (or gusgus), which is a rather ambiguous association to me, as the band was cool in the 90s but has been crap ever since.
In the 2005 movie "12 And Holding" there was a character called Gus Maitland (portrayed by Jeremy Renner). He was befriended, and eventually (unsuccessfully) seduced by his therapist's daughter, Malee Chuang.