If you don't plan on using a phone much, just get a cell phone. They've got
lots of plans that range from about 2,000 yen a month on up. The best phone
is the one you want. They all work and the coverage is generally excellent.
Much much much better than what I've seen in the states.
Landlines are more and more just being used for internet connections, by old
people, and by NHK in their morning family dramas.
A lot of transient gaijin don't bother with a home phone and just use a
mobile for calls, messaging, e-mail etc.  NTT DoCoMo is preferred out in the
sticks (best coverage) but I guess they're all much of a muchness in the
cities.
As for having a social life - get a mobile.
--
jonathan
Since you're from the US, I would say that unlike there (so I hear), a
mobile cannot really replace a land-line, so you probably need to
investigate both.
Also, mobiles are bought with handset and usage contract together
(usually for one year, with penalties for early exit (but there are
prepaid mobiles, although epensive)), and all four big networks
(DoCoMo, JPhone/Vodaphone, Tu-Ka and Au/KDDI) are basically pretty
much 100% over all major built-up areas and call quality is pretty
much the same. As to what are the best phones, what do you want? Each
service provider has lots of different models with lots of different
features at lots of different prices, from zero to 30,000 yen a go,
and of course lots of different usage pricing plans. Decide what
features you want first.
As for landlines, NTT is the main provider. You have to buy your
telephone line for 70,000 yen from NTT (or they do a cheap rental
scheme, 400 yen per month or so), or get a second-hand one, which
shouldn't cost more than about 25,000 yen. There's about half-a-dozen
phone service providers, I use G-Call myself. There's also a few
companies doing VoIP phones, which, especially if you do a lot of
overseas calling, is a nice add-on to an ADSL contract.
Price-wise, mobile usage is much more expensive than the US, I think,
land-lines are about the same, but ADSL is dirt cheap and much faster
- 8Mb/1Mb is low-end, they're advertising 24Mb these days.
Ken