Trollo: good to see you (and seqretary) are still alive!
I'm just about to install the latest update, and I look forward to the release of what's still in development.
A few comments:
- One issue I've noticed is that it is possible to create an event of such a short duration (e.g. one minute) that it is impossible to delete, due to zooming constraints. I did this without thinking, to essentially function as an alarm for a recurring event of negligeable duration, and now I'm left with a choice between putting up with it ringing every evening when I don't want it to, or scrapping my whole calendar and re-entering everything. That falls partially under PEBKAC (on my part), but I also feel that it's a bit of a usability problem for the application as well. I'm not sure what the best solution for that is (maybe put a sensible lower bound on duration (say, 5 minutes), and add an alarm feature), but something should probably be done when you have a chance.

- If you have decided yet, are you planning on writing your own stand-alone todo system, or one based on (or synced with) an existing service? Judging by your work so far, I wouldn't be surprised if you had something unique and awesome up your sleeve, but if not, merely getting a good feature-complete and stable app out the door that syncs with, say, RTM (with local-only optional) would be awesome, and the more so for your excellent design and usability sense.