What do you want to do, and what can you do?
My path was to have a lab at home. I have 5 servers, 3 switches, 2 firewalls, and 10 virtual servers in my basement. This is across 3 subnets, and 3 Vlans.
Having a enterprise network in my home helps me learn.
If you are going the microsoft or cisco path ... learn and get a MCSA/MCSE or a CCNA