mehran9o

I recently bought a road bike and I don't know which computer I should buy!
There are wireless and wired, and there are waterproof and there are ones with big screens.

I am not planning to race with my bike, yet use it for training. I also have a heart rate monitor watch which can measure CAL and Heart rate and has couple of other functions for training. I might have to cycle when it's rainy. And I don't think I need navigation system for my bike right away. I also want to keep the bike light.

--Do you think computers with big screens and more functions are better than the small ones with tiny screens? Which are more practical for trainings, etc?
--Should I get a wired computer or wireless or does it all matter?
--And most importantly does it have to be waterproof? Do you think that a non-waterproof one also works in a rainy weather?
--What brand should I buy! (something that lasts long). What model?
If the colour is black and white it's a plus!

Thank you!