You're paying quite a lot for a very weak VPS--compare at slicehost or linode. So your first step might should be to spend less for a more powerful server at on

You're paying quite a lot for a very weak VPS--compare at slicehost or linode. So your first step might should be to spend less for a more powerful server at one of the other VPS providers. OTOH, I'm not sure linode or slicehost even offer the kind of support package that you have paid for with midphase--you'd be on your own. OTOOH, if I read your post right you're paying midphase $130/month currently. You can get a whole lot of server for a lot less than that. For some combination of Drupal's general heavy-weightness, lack of caching, slow server, your front page performance is sporadic and mostly very poor. I get times mostly in the 0.6 - 1.4 sec range just for loading the HTML, and that's with about 0.15 sec as the baseline for just loading a similar-sized static image from the site. I'm not a Drupal expert even a little, but if you could fully cache the front page (so that apache serves a static file directly) and update it, e.g., once every 10 min, you'd be flying, comparatively. But about what's going on, I'd lay money it's all of the above: you have a low-resource server, drupal isn't fast/light by default and you haven't made it any better, you're not using any caching where it would really help. You should work on fixing all of those.