Advertising Anyone?

Managing Oncalls and Medlogs is not so demanding .. but as our traffic increases .. so does the cost.  Here's Medlogs.com's traffic for January:

Successful requests: 9,641,953
Average successful requests per day: 34,842
Successful requests for pages: 1,163,362
Average successful requests for pages per day: 4,204
Distinct files requested: 22,320
Distinct hosts served: 40,582
Data transferred: 108.525 gigabytes
Average data transferred per day: 401.590 megabytes

No wonder the hosting fees are going up!

The Google ads are generating some revenue – but not much. 

I'd like to host some advertising on medlogs.com and oncalls.com, but I'm hesitant to do so as I really hate seeing ads on websites myself.  The right ads would have to be well targeted, and ideally text only. 

Ads on OnCalls would allow us to shift from a subscription model to an advertising model.  Many of our users would like this – even though our fees are quite reasonable.

Hmmm.

Any suggestions?