The only "low" that I can think of is that you have to pay some extra bucks for the network. However, the highs are piling up like the sears tower. I think it is really fun to do networking, and it is very useful.
Obviously the trend is that there are going to be more than one computer in each home soon. However, there isn't a trend that every household will get an extra phone line or DSL line for a new computer. So networking is the only way to go.
Networking is actually easy, which the help of nowadays software. for you that only have two machines, the cheapest thing you can do as a tryout is a crossover cable. it is cheap, and you can taste how networking is like.
later on when you get more than two, you need a hub or a switch, that will be more interesting, but i think it still worths. I have 3 computers at home now, and i never regret to setup the home LAN.