well too me i'd rather increase on the SEO, like say climb to the top of other "Keywords", let say with google webmaster (assuming you know), there's probably 20 most searched quarries for your site right?? get them all up to the top 10 least, and with google analytics see what keywords people searched to get to your landing page, don't tell me all your pages have the same keyword??, and without a doubt you have different articles written to different landing page of your site right?? if so add more content with articles pointing to those content, and see if the most search quarries section has that article's keyword, maybe that'll add more traffic, all and all just add content, and i really like the idea of a contest giving away free "ipods" i'm in~!!!
What about considering a viral marketing campaign? Running some kind of contest can generate a mega amount of interest in your site which can very well end up turning into loyal traffic.
Thats a lot of visitors per day. Can you share some tips or show how you achieve that number of visitors