Should I decide to move my 120+ domains (only about 2 gigs of data) hosted on a plesk platform to another provider, are the any webhosts that include such a service (i.e. they would copy all the stuff + email and ftp settings etc.)?
There are hosts that will cetainly do it. You should prepare a list of hosts that you like, then contact each one individually and ask if they would do this.
I recommend that you pick one that is very technical. Companies that own their own servers/co-locate them tend to have more technical knowledge, IMO.
Ask a lot of questions before selecting the company. If you get a gut feeling that a company is too slow or not technicall apt at doing this, then you are probably right.
Well see my previous email about email hosting as to why I would want to leave my previous host, but anyway yes I would like another Plesk host as I like that control panel and feel comfortable with it. Would I just need to give the new host my username and password and then they could move ho whole thing?
Regarding b/w and storage then about 500 gb b/w a month and 2 gigs is more than sufficient.