Don't all shout at me for stating the obvious, but uplink speed is as important as downlink: all the megs in the world coming down to you with a slow uplink connection won't seem very fast.
Here in Spain WiMax is widespread - I connect with a tower about 15kms away - and "only" have a one meg connection, but it's a constant one meg up and down. Gives me all he speed I need, and costs €45 a month including IVA (VAT).
As with everything, you get what you pay for: TANSTAAFL !