Would be considered old-fashioned now I imagine.
I get a mental picture of somebody stuffing a 'Pooh-bear' type stuffed animal like Rupert on Family Guy wondering to myself "What the hell do they call those people?"
Transvestite would be offensive to most transgender people if it was used to describe them, but I don't imagine that most actual transvestites would be terribly offended by it
The T slur, however, is one that I think is universally offensive to cross dressers and transgender people alike (generally speaking, obviously)
"Cross-dresser Replaces the term "transvestite"."