I inadvisedly bought a Bianchi hardtail a few years back when I got back into MTBing (my first MTB was a Spesh Hard Rock from the early 90s). I did't see the importance of geometry and simply didn't "get" that fact that riding "XC" was not the same as riding "Trails". A super long stem, low flat and narrow bars and heavy 80m forks meant for a distinctly average ride. 12 months later I went out a bought a spangly full susser.
Cutting a long story short, I've recently dug out the Bianchi and invested in some new bits; shorter stem, wide low rise bars and rigid carbon forks and now the bike is AWESOME. It feels spot on and the stiff alu frame accelerates like no one's business (the one good thing the bike has always had). Granted it's not the bike of choice for the big mountains, but around my way it makes me feel like a cross country god.
Anyone have any other success stories?