which service for iPhone?

 Hi, I am going to have to have a smart phone now (the reasons are
unimportant just trust me). ;-D

I am very much leaning towards the iPhone due to many reviews
including my sister's raving reviews of it.

So now the question is:
Which service do I get and what is the cheapest I can pay for phone
and internet service?
I have determined that about 1gig a month would probably be enough to
handle my use of the net. As for phone service I probably won't need
more than an hour a day of local calling.

I use onesuite.com for all long distance. Not sure how that jibes with
using cell phone service, I have been using it on my landline but I'm
getting rid of my land line. I do have a magicjack at home that I can
make ld calls on as well. I will occassionally have to use the iPhone
for ld but not daily.

I have heard that ATT service sucks in L.A. where I will be using the
iPhone. I have heard that Verizon is best. I welcome opinions from
anyone who is currently using an iPhone in L.A..

The basic questions then are:
A) What is the best service (i.e. service that works from almost
anywhere without problems) in L.A.?
B) What is the cheapest way to get that service without locking into a
long term contract? I'd prefer to keep any contract at a year or less
however if necessary I could go 2 years but would prefer not to go 2-3
years.