DL has more fees/surcharges for straight redemptions than CO does. CO change fees are higher. CO is moving to Star Alliance at some point next year so that will significantly change the partners available for redemption soon.

CO is installing LiveTV starting in January '09 on all their domestic-focused planes, but it will (is expected to) cost $6 in Y for the TV bits and no charge for the "internet" bits that they offer. DL is installing Aircell on their whole fleet for paid internet and they have some of their planes with TVs that are free but they are not planning on installing them on their MD88s, which are a huge chunk of the fleet. Neither is putting IFE on their regional partners and Delta uses them for something like 60% of their domestic flights according to Sky magazine in August.

Lounges are pretty similar. CO's wifi is free for everyone and DL's is only for people with CRC memberships, so there are some limitations there, but nothing significant.

I think that the other bits are all a wash.