I have come from a VPS, which I like the performance and quality of but a dedicated server offers you so much more, you are in control of the overall load of that machine. Even with VPS, scripts can run out of control and slow down your machine. I have had this with UML and Virtuozzo. Now at least for me it did not happen often but, I like the full control and power with dedicated.
You might want to think about a Athlon instead of a Celeron, more power for the buck.
i agree dedicated server will be better but not every server is goodand not every provider is good.
Jippi said he is thinking to host 100 normal websites with low traffic so if i have to choose between that celeron he said about and a vps from servint or powervps i should take the vps and not go with very cheap dedicated.
Jippi think twice and read past experiences you can found in this froum.