I used to run a for my high school XC team, I was never too great of a runner as I did it to get in shape for hockey mostly, but it did a helluva job of keeping my weight down and I never looked better than I did in my running days.
For shoes, I always liked the New Balance trail series, the pairs I wore were usually around 120-150 and I got last years stock at Tel-A-Run for 80-90 (
http://www.telarun.com/index.html). I loved the 904's cause I have pretty wide feet and nothing else out there really fit me right. Tel-A-Run carries all the big brands though, if you like Asics they probably have a great price on them, good customer service too.
There's a lot of different performance underwear out there, I just wore cotton boxers and lacrosse shorts, but the guys who liked the real short running shorts usually wore spandex cause it wicked sweat and it kept the ol' johnson from coming out of short shorts (which happened all the time with boxers, lol it was great to see the looks on spectator's faces). I think under armour makes a pretty decent pair IIRC, I loved their tight fit shirts under a loose fit grey performance t-shirt, sweat was never an issue.
We used to do a whole lot of different training routines, a lot of it centered around hills (since we were in Maine) which you probably don't get out in Texas. For improving speed, we used to do all-out intervals of 800meters, with roughly equal rest and run times (group 1 would run full-out while group 2 rested, then they'd switch). The shorter-length high speed runs are what really improve speed.
Consider tossing in some short sprints (100yds full-out) in with your distance routine, they hurt but you'll see a big improvement in conditionining over time. Pushing yourself all-out is what really improves your times, not running 3-4 miles at a decent pace. With the training we had, I dropped my mile from 14 minutes (yeah I was in terrible shape) to 7 flat in 2 months.
Getting a good music mix set up that you like is a big part of it, they wouldn't let us run iPods on competition as it was considered an unfair advantage, I think people ran like 10-15% harder with a good sountrack if I remember right. I had a house/techno mix setup for running, I got songs where the beat was just right for my running pace and it helped me a lot with training.