If you feel confident in an original, do that. I think it's always more impressive to hear a well-played original song than an exceptionally-played cover. But maybe that's just me.
I'm with Pittman, Warehouse is tough - but if you can pull it off well that would be quite impressive. I say whatever you feel more comfortable playing. by playing Warehouse, you may be judged more than if you played one of your own. anyway, just my .02 cents.
How bout The Stone. That is usually an impressive song. Lyrically it's really cool, too. Not that warehouse isn't, but The Stone is more easily understood.
