I got it to work! I had installed a series of downgrades/upgrades to unlock my Touch's GPS (I'm with Verizon), but then my phone showed the roaming triangle at all times as well as the "Preferred System" text under the time.
After reading
this thread, I set my PRL to the newest Verizon one by downloading the latest Nationwide PRL zip at the bottom of the first post and copying the files inside to my SD card, going to Start -> System Tools -> Phone Codes -> PRL -> (Menu) Edit -> choose PRL file. Curiously, the PRL field was empty before I set it. Anyway, after the reset, my phone picked up the VZW network and doesn't think that I'm roaming anymore. Yay!