Definitely a plugin issue, good guess Masshuu. richard: you've got around 49 plugins in the plugin folder. I can't see how many are actually activated, however that is most definitely the problem.
Among the list of ones known to cause problems, you have at least one, WP-Super-Cache. Supercache sucks up a major amount of CPU generating and saving the static versions of all the pages on the account, so I'd definitely disable that if you can. Same with the sitemap generator, although I'm not sure that one actually uses a lot of cpu.
It's definitely gunna be related to just how many plugins you actually have installed though.
