Well, there's already a vBulletin equivalent of this thread, so why not an Invision Power Board one considering how many products they release? Personally, I use most of the suite except Content and Nexus. I don't use IP Content because I think Wordpress is more well supported and probably easier to use (and it being free helps too), and I don't use stuff like Nexus because I'm not running an online shop, there's no use for it. I also don't use IP Chat because I think the pricing is rather high (I'm suspicious of any 'per user' pricing schemes) and a chat room doesn't really strike me as needed. However, I do use the forum, blogs, gallery, downloads and that seo app they released in the marketplace a few months back. All are rather useful for my website.