Check largeformatphotography.info for lots of information about getting into LF, camera reviews, and such.
My first LF camera was an 8x10", because I like contact prints, and I preferred working on the larger groundglass with the idea that the final print would be exactly the same size as I saw it when I composed it. Now I shoot 4x5, 8x10, and 11x14, and each has its place. I still prefer 8x10" to 4x5", but sometimes the ease of use and quick setup of the 4x5" makes it a more practical option. If I'm out in nature, I'm more likely to be under the darkcloth with the 8x10", but if I'm in a city where cops are suspicious of tripods and you have to keep an eye on your equipment all the time, I'll use the 4x5" with a folding viewer.