I used to use Eudora, hated outlook express but now use Outlook for everything.
Firstly I organise my main categories:-
Business - Mycompany ltd
Business - Other Business
and many more..
I then use my calendar to map out my regular tasks everyday which I view on a 5 Work week setting.
Once I have all my regular tasks entered to re-occur every week I then see what little time I have left for real work.
Now, every day I spend 15 mins sorting email, I either Do it, delete it, delegate it or defer it.
If its something I can do with in a minute I'll do it straightaway other wise i move the email to a category in my tasks list ready for planning in my calendar.
With in 15 mins my inbox is empty again and all filed into the correct sections and emails downloading quickly.
keeping track of contacts is just as simple.
I used to hate Outlook but I've learned to use it correctly and I know many people hate using M$ but I've not found anything better and so widely used, specially important when others also plan using outlook and send you appointments.
For me outlook is the best for now, I've tried Eudora and other calendar software etc but outlook works better as its altogether under one roof.
One day we'll sign up to the exchange server then the real power of Outlook will come through.
Added - I leave Outlook to work in the background just by shrinking it, whenever I need it I just click and it opens quickly. I don't have send and receive on automatically as this can disturb you everytime something comes in, also you may want to adjust emails that you'll send before sending.
Another good tip is to free you mind of ideas, thoughts, post it notes, text messages etc by entering tasks into the task pad then move each task at the end of the day into a category ready for planning in your calendar.
Its amazing how much you store in brain thinking of all the things which outlook could look after for you. We've all been their, forgetting things the wife says about going out for dinner or planning a shopping trip :( thats because your brain is overloaded and its best to have all this stuff stored in one location then sync with your mobile or PDA.
Their are some really good books on how to handle email and time management.