I went through the exact same thing a few years back, and even tried Mingle. I found it great; very flexible and certainly the prettiest out there. But I ended up spending more time managing myself than doing the work; not good.
I've since settled on Fogbugz, and not looked back. It's true strength lies in dealing with the management of software projects though, so if you're after a general purpose "you need to comb your hair this morning" management tool / to-do list then it might not be the best fit. The best feature by far is it's ability to statistically analyse your previous task time estimates vs task time completions and apply them to upcoming deadlines. The result is that it predicts the real likelihood of meeting a project deadline with scary accuracy!
A more lightweight to-do list style service is Todoist. Amazingly minimal, but really flexible and useable as a result.