Since i have no clue about this, i'm sure you'll all be able to guide me in some sort of direction.

I have a 05 Giant OCR1 with Shimano 105 components and am wondering if it's worth upgrading the brakes etc? Prior to purchasing the bike second hand, I had no idea of the difference in components out there..

I don't want to buy a new road bike as i'm still not fast enough on the one i've got and it can't be more expensive than my lovely (Scott) mtn bike . I'm not a true roadie ya know.

Thoughts?