From what I have seen, Aggy is the equivalent of the TU thing. I see it all the time on ESPN comments and message boards. Some of the more antagonistic people like to put an F in front of it, or say "aggot" too. If you go to Txags, you will see a lot worse names than TU or Tsip as well, but this is the internet, so everyone is a tough guy.
I personally think it's all pretty stupid, but I'm not real big on A&M traditions either. Usually it's the more indoctrinated folks who use those slurs, especially the Corps. Corps guys, more than anyone I ever met on campus, push those traditions of hating UT and everything with a hint of orange. They also have a lot of stupid and, to put it frankly, homosexual traditions within the Corps, which give the rest of the school a bad name. Those guys are pretty weird, but they have a huge voice at A&M, so they tend to keep a lot of these traditions alive, such as referring to UT and TU at every yell practice and staving off even the least bit of changing the way we do things.
Personally, I'm hoping the move to the SEC will remove a lot of that stuff, and I hope they make an effort to change the songs as well. Shifting the focus from hating UT to our new rivals, or just propping up A&M in general would be much more preferable... but I'm probably in the minority on that.