I've been trying to decide between commuting with my road bike, or with my hybrid with panniers. I prefer the road bike, as its an 8-10 mile ride depending on route choice with some decent hills. I will only be commuting one day a week (Fridays) so I think I've decided to stick with the road bike, and bring my Friday clothes with me on Thursday. I have doubles of toiletries anyway that I use for the gym, so I'll pack a bag on Thursday with my extra toiletries, towel, and Friday's work clothes and shoes. Leave it at the office Thursday, then stick my wallet, keys and cell phone in my little saddle bag on the road bike, and everything I need will be waiting for me at the office. Then I can just bring it home with me on Monday, since I won't need my extra toiletries or my Friday work clothes over the weekend.

If you are not commuting daily and you'll know in advance what days you'll likely be biking in, this may be an option.