Live with a brother, never lived alone.
I do feel it would be good to live alone for a while and it's something I've given quite a bit of thought actually.
I'm quite happy in solitude, but to try "living alone" would mean renting a small place in town, lugging all my stuff over there, losing access to a ton of creature comforts and appliances and having to apply for a phone line & DSL again...
The current setup is great as we're both very similar in our wants and tastes, so we can comfortably share 4mb uncapped DSL, projector room for watching stuff, PC room for both our rigs which is ideal for having company / gaming together, take turns sorting food, packing the dishwasher, can do laundry together, share the downloaded stuff (series), etc.
Pretty efficient system which halves the work and reduces the "human need" for company / relationships.