I have 6 Raspberries Pi: two 256Mb, two 512 Mb and two RPi 2. All are Model B/B+.
I have run RaspBMC for years, now OSMC.
I have one Pi as a Domain Controller (WebMin/LDAP/SMB).
I have run one Pi as a Webserver for years: it does 400,000 hits, and serves 20GB data per annum.
Read my book: "All about your Computer" at http://www.lulu.com/kaspencer. I absolutely know you'll enjoy it! Starts easy, get a bit technical at times!