I'd stick to any kind of contextual links pointing to your site + social signals (likes, tweets, +1's, bookmarks) slowly building up in velocity over time. Then I'd hammer the tier one contextuals with TONS of profiles, SB blasts and even blog posts if you can get them cheap enough. If you really want to make it worth your while build a multi tiered pyramid and hit the whole thing with as much fire power as you can. All the while maintaining link velocity directly to the site via other contextual links.