So my question is, what are the alt currencies that interest you, and why? What do they bring to the table that BTC does not?
From my perspective, the most interesting alt currencies are the ones that grant the most anonymity (Zerocoin comes to mind). Bitcoin is a great step. However, it is still traceable. When an alt currency becomes as mainstream as Bitcoin is today and grant the same anonymity as a fiat cash transaction then we will have something.