My old O2-contract expires shortly and I don’t have a wish to extend it for the next 2 years. I think about a contract with BASE with phone flat rate and UMTS flat rate.
Yes, I know, it is not a real flat rate, because I may not use VoIP, but currently it is the best offer in German market of mobile services that I know. I will use UMTS for reading of emails, icq chat and www.

Do you know about 1&1 Pocket Web? It could be a interesting alternative for UMTS, because it costs only 10€ monthly.