the Sound System...
Over the years I built up my sound system and eventually ended up with something that sounded great.  Not high volume or chest pounding...just high quality.  I did all of the installation work myself and while it was challenging it was a lot of fun.  Not.  But the end result was worth it all.

DISCLAIMER: Even though I have an Eclipse Head Unit and CD Changer I DO NOT endorse Eclipse, typically referred to as "E-skips".  I also fell that their customer service is terrible, particularly Bill Heinlein...a very dishonest and rude individual.