We're looking at moving our office shortly and we'll need to get our own internet connection (we currently have a 7Mbps LAN connection in our current building).
We're based in the UK (centre of London) and we'll need at least a 5Mbps connection. We currently have 10 in office people with 2 VPN users: however, we'll be looking at expanding (within 2 months: hence the need for the new office) to at least 18 people in the office and 6 VPN users. We would also like to use the internet connection for Voice calls using VoIP. 4 people tend to use it for basic email/basecamp work (around 5-10Mb files), others a graphic designers (50Mb files), a couple watch streaming video from time to time (mainly the big boss), there is some online game play (not MMOs though: more flash games) for research and then 3 developers working with around a 100Mb code base.
Given the choice between a leased line, ISDN lines, Bonded ADSL or just a bunch of ADSL lines: which would you recommend and why? Any you would particularly avoid and why?
I know my choice/recommendation, but I'm asking here as somebody else here has a widely differing opinion and I'll like to check with true techs!