Good GTD app

I'm looking for a good GTD app for my iPod Touch. There seems to be a bunch out there, so any advice?

I'm just looking to remind myself of jobs and such. Simple things that I don't need a lot of power or depth for in a program. I'd like one that has a desktop companion program, syncs with the desktop companion, and could possibly sync with iCal. I'm not as interested in a program that is internet based.

I've downloaded the trial of Things for my Mac and am very impressed, with it's simplicity and the fact you have it there in your dock with reminders. But upon release the program will cost $49 ($39 if you sign-up for newsletters) and the mobile app costs $10. I'm finding it hard to justify that kind of money for my needs. Is there another program out there?

Thanks.

On a side note, I find it odd Apple hasn't addressed this and provided a solution for getting iCal To-do's on a Touch/iPhone. After touting the fact that mail and iCal in Leopard contained To-do's and Notes. And it doesn't sound like the next update has a solution either. It seems like Apple picks strange problems to let 3rd-party suppliers solve: landscape email typing, getting files onto devices (disk mode), To-do's...