what is the best way to upload large amounts of data?

Hi, I currently backup my customers data to a local server using Ahsay data backup software. However although I am sure that the server I use is good for the purpose I am considering using a dedicated server so my bandwidth is not used up and so that customers data is safer etc. My only dilema is that some of these accounts might be 100's of GB's and I have asked many of the dedicated server companies if I can ship the data to them using a USB hdd for example and they have rules that state I cannot do this. I am considering going with BE unlimited broadband due to the fact they have an upload speed of 2.5mb.  is there any other bband providers that have a higher upload speed for this purpose or is this ample to say FTP the data to the dedicated  server?  I am with virgin so that doesnt really help in the department of dynamic IP, though I have got round that with dyndns.org. I definately want to go down the route of a dedicated servere and have looked at ovh.co.uk has anybody had any dealings with this company they seem to be pretty reasonable. or is there another way of being able to send large amounts of data to a dedicated server without purchasing say a lease line?

Thanks in advance.
Chris