The only hardcore games will be fighting games, mostly 2D ones because the majority of 3D titles just don't get picked up competitively for one reason or another. Fighting games aside, they had a Rock Band and DDR tournament for the more casual gamers.
As I've been attending the MCM Expo for three years without fail, I've slowly met people which I ended up bumping into at the LAC. People I very briefly met two years ago at MCM were actually recognising me at the SSF4 tournament, this was great.
Attending the LAC has encouraged me to find more meet-ups for video games and anime. I'm interested in taking part in the social aspect of my hobbies a lot more instead of coming home from work most days and watching anime or playing video games (or doing more work at home).
Neo Empire, which is the UK's biggest fighting game community, has a London forum where people arrange regular meet-ups to play fighting games in a LAN environment. These are not only great for socialising, but the players you find here are far more skilled than the average noob on Xbox Live or PlayStation Network. Naturally, anyone who is interested in attending such meet-ups is nearly always more serious about these games compared to the average joes who just dabble in it.
On the anime front, I'm always on the lookout for any and all London based conventions which look promising. I now have MCM and LAC to look forward to each year, and I'm sure I can find a few more in London if I sniff about.
@Michael - You're more than welcome to come with me to any of these London based events, I don't mind the company. The fighting game scene is very strong in London when you compare it to the rest of Europe, so I plan to take advantage of this luxury.