I seem to be experiencing a bit of a handling problem with my bike. I've recently replaced the factory riser bars with Easton flatties and the steering has become much less responsive. I presume I'd be best off getting a shorter stem to counteract this problem? Also, will a less angled stem help in ascents, as my positioning will be further forward over the bars?

A longer stem will help if you have a problem with the front wheel lifting/wandering when climbing, but otherwise no. Why did you go for flats? Personally I find them too narrow - your bars should be a bit wider than your shoulders, and you should find that the arms-wide position helps open your lungs.

Since you're obviously not a fashion victim you could try a shorter stem and bar ends. That will give the extended reach forwards that you need for climbing, while allowing a shorter stem for faster handling.

"Since you're obviously not a fashion victim..." LOL! I try to remain individualistic if I can (hence shirking a Specialized in favour of an RM)!!

I guess I went for a flattie bacuase I prefer the feel. The riser bars just felt.... odd. Thanks for the advice, RM, I'll give all that a shot.