OKOK listen up.
you DO NOT need 100mbps internet.. PERIOD.
I have 10mb, and it's still much faster than I really need.
People play AH with dial up with no problems... let's put this in perspective:
Dialup.. under ideal conditions is about 56k. 1mb is about 1000kb. Realistically you get 20-25k out of dialup.
This means that 6mb is about 240 times faster than dialup! (100 would be about 4000 times faster!)
With most online games, latency is the key, not the speed. Latency is how long it takes a packet of data to travel from your computer to whatever server you're connected to. Regardless of speed, just about any DSL/CABLE technology is going to have a very low latency (probably 5 to 6 times less than dialup).
The only time you really benefit by having super high speeds is if you do a lot of large downloads at a time. Even when downloading, you're still capped at the speed of the server that is sending you data.
Lets say you have 100mb internet. The website you're downloading from runs off of a 20mb server. At best you'll only get a 20mb download speed (most likely even less if several people are downloading from them at once).
Save your money, drop down to the 6mb service. Most likely you won't even notice the difference.
Just like a chain is only as strong as its weakest link, an internet connection is only as fast as it's slowest connection...