I held off getting a cell phone as long as possible, but was finally convinced to get one for my recent move. I don't have a landline, now, and use it as my sole phone.
Before I moved I knew nothing about such matters, and a friend recommended T-Mobile. I got a cheap $20 plan w/ $5 additional for T-Zones (data / net functionality) and a
Sony Ericsson T610. It was a neat phone, tiny, with a crappy camera and pretty nice data service support (good for MapQuest, white pages and such). However, the T610 is known for having poor reception, and what do you know? At my new place it got 2 bars at best, and dropped calls like clockwork.
I took it back within the 14 day period, and had the number switched to Cingular. I almost got the T616 (same as T610) but the Cingular sales lady acknowledged the poor reception problem. On her recommendation I got the
Motorola V400 instead. So far it's been pretty wonderful in terms of reception and coverage (though I've not traveled much). It also has a TFT screen, which makes it much easier to look at than the T610.
Cingular's costing me about 40 a month -- 30 for the base plan (national, all the minutes I could need) with insurance and 1MB data transfer making up the rest. The data transfer is a sore point of this setup, as the 1MB can go pretty quickly and I'm spoiled by the unlimited access I had with T-Mobile. Cingular's web features are also lacking compared to T-Mobile's.
For example, with TM I could track up to eight movie theaters and check them at any time. With Cingular it seems I can only subscribe to one, and the data is pushed to my phone at regular intervals, eating up my data transfer allotment. Yuck. Cingular also charges extra for MMS and AIM / IM support, which were both free with T-Zones. Needless to say, I can't justify $3 extra per month, each, for such superfluous (though fun) features. Luckily, it does appear you can trick the phone a bit to send pictures to email addresses w/o paying for Cingular's MMS service.
Just as an aside, I hear T-Mobile and Cingular use the same towers. So, the reason I now get useable service at my home is likely due to the phone itself being better.