I've attached my current card. Some thoughts in no particular order.
I like business cards with rounded corners.
The tag line should be "iPhone / iPad Applications"
I'm not tied to that particular bass or showing the entire instrument but do want to keep that theme.
I like the use of color though am not tied to that scheme or approach.
Currently the bass is hard to see.
Final product should be of appropriate size and resolution for printing on standard sized business cards with rounded corners.
Letter head should be appropriate size and shape for standard size letter paper.
Sponsor Logo should be a more compact version (square) of the bass and company title appropriate for t-shirts and conference sponsor pages.