I'm not sure about TNT in particular, but I watch what most would consider far too much T.V., cable and satellite, and I can't think of a single time that I've seen an Angel rerun, on just about any channel. Now, I grew up in Canada, so maybe the stations vary a little bit, but Buffy has always been syndicated (usually on MTV, or MuchCanada, the Canadian equivalent), usually several times per day, but not so much on the Angel front.
I hadn't really thought about it, mostly because I have the DVD's and watch those fairly regularly, but it does seem a little strange that it hasn't been syndicated more (or in Canada, at all). I mean, it ran for more than 100 episodes, and that's typically the benchmark for major show syndication. I see shows like Buffy, Smallville, Supernatural and a number of others that have run for that long have re-runs aired all the time, but not Angel. Don't get it, really. It's an awesome show!