This is my first post on this forum, but being that this particular subject seems rather apt for my situation, I figure that this is as good a place to start posting as any.
I used to play back in college for a couple years, but my studies and work wound up taking all of my time and I ended up not playing anymore. After the recession hit I become unemployed for a time, I finally decided to sell all of my basses(didn't play them and I needed the money). Anyway, my first bass was an OLP MusicMan fiver. It wasn't my main bass, but it was a good bass that was fun to play and being that I am lazy, I find it an excellent alternative to dropping my E on a four string bass.
Long story short, my financial situation improved and I started jonzing to start laying down some sweet grooves, so I decided to get back into bass playing again and I made the conscious decision to start out with a five string bass and here's why. First is the versatility, being that I wanted to be able to have that extra range without having to drop tune or buy any extra basses, a five string bass is ideal for this. Then there is the skill area, most five string basses have a wider fingerboard and tighter string spacing, if you manage to get good at playing on a five string, whenever you pick up a four string bass, playing will usually become that much easier(at least for me anyway).
I wound up getting myself a Washburn Taurus five string, and if you decide to go with a five string, I highly recommend it. It is relatively affordable as basses go(usually about $500 new at a guitar shop) and IMHO good enough quality to keep it as a main player as you get better down the road. From what I gather, opinions differ as to the sound, but being that it's a well built neck thru design, that issue can be solved by upgrading the hardware and electronics should you feel the need.