As some of you may know, I now always cycle as my main means of getting about around the city as its quicker and more efficient for myself personally. (Sit in a traffic jam for 40 minutes falling asleep or spend 20 minutes on the bike, riding like twat, cutting up cagers, jumping the lights, hopping kerbs, scaring pedestrians etc .... tough choice

).
(No I can't use the motorbike as the secure parking facilities and ground anchors at uni have been removed

).
However, I bought a 21 spd full suspesion mountain bike but I don't like it as much as my cousins road racer bike which I was fortunate enough to have quick a go on (he paid about £650 for his). I have been looking for a new bike on the net all night and I have found a couple that I fancy at the best prices in the UK (off the net). Before parting with my cash I have a question about the gearing on road racers compared to mountain bikes.
The gears on road racers tend to be between 16 and 18 speed whereas the mountain bikes tend to have 21 - 24 in general. Would the racer with fewer gears be faster than the mountain bike as the cogs are likely to be designed biased towards speed and the mountain bikes have some additional cogs simply for off-road/hill use but don't deliver the same speed on the road even if they were in top gear compared to a road racer as the cogs are designed for off-road etc?
Or simply put - would a 18 speed road racer open a can of whup ass on my 21 speed mountain bike?
I have my sights set on this if my thinking above re: gearing is correct as the mountain tends to run run out of steam and when I used to cyle in my earlier years I used to go faster!!;
£399!! fecking bargain (RRP = £500) comapred to other outlets - anyone know where I can get matching Lycra