A dedicated solution will give 100% of the resources directly to your websites, where a shared solution will require you to share those resources, and you may only end up getting 1 - 2%, if you end up using a lot more than this most shared providers will request that you move.
MrRadic, do you mean i will only get 1% or 2% of the allowed bandwidth with shared host ?
He was referring mainly to CPU usage, but yes, it also means that in few scenarios you'll be able to use all those 1000Gb that you're allocated. One such scenario is files distribution (mp3s, clips etc.) Look out for clauses in the TOS that limit the way in which you can use the account though. Some hosts will not allow you to use your account that way.
1tb of data transfer costs hosts ~$50-$60 per month period.
If they then resell that to you for $10, they are losing money.. Why do they do it? They assume most people wont use 1tb a month. And the ones that do? Usually they can be booted for too much CPU usage, violating the TOS, etc.
Have you considered Semi-dedicated Hosting? 4 - 8 accounts per server. Less overhead than VPS, better performance for the price. DopeDomains.com - 15,000 New Domains a day. indexed by Pagerank, backlinks, Hits, and Length.