I have about 15 developed websites, but I'm still fine with two shared hosting accounts, as my sites are not receiving so much traffic (yet). However, I consider moving to a VPS or a dedicated server in future when my bandwith usage will grow dramatically (if this ever happens).
I have 4 or 5 sites. All on shared hosting once they get more traffic and need more resources I'll probably change to a VPS. When I used to do proxies they were on a dedicated server
Two sites on two different shared accounts, use different companies, I started the first one when I was learning the ropes about using hosting, and went for a small company Hqhost.net, beeing a loyal customer I'm still using them, but my second site is hosted with a bigger company ServerPoint.com, have fun using both, whenever I'll think of more serious things to do on the Internet and make money online, I'll move to ServerPoint.com VPS.