How many accs/top level domains should i host?

[nomi]

Hi i just bought a new:
2.4GHz P4
40GB 7200RPM
512 MB RAM
100MBPS Port at EZZI

Anyone advise me on how many sites i should host on this and still be able to keep it stable.

[Imago]

Depends on the sites. If they are heavy DB-intensive forums or cgi-based feeds, then three of them may consume all your resources, especially when indexed by SE bots.