The USA DC launch was the best for any console ever (well bar the Pal X-Box launch) . I got my DC in December 1998, but the USA was amazing . I still remember my and my brother being jaw dropped playing NFL 2k - Not only was the graphics,animation and commentary in another league, its also played brilliantly (still better than any Madden post 32bit title) and made great use (if not the best) of the VMU (with its play calling).
Some of My fav DC memories are as follows...
Quake III - My 1st ever experience of playing head to head online gaming .
NF2 2k - Me and my brother playing this game for hours and on end and one of the few games my bother was genuinely good at
PSO- The most magical gaming experience of my entire gaming life . Truly a game of friendship/companionship and and just a complete magical experience
Code Veronica - For me hands down the best DC game ever made, and the best RE game too. The best plot and set of characters ever to grace RE world and at the time, the best looking game on any system be that Arcade , Console or PC.
GetBass - Most prob the best party game ever, and me and mate still laugh at the thought of his Father actually pulling a muscle playing this game lol
VO II - For me the best GFX ever seen on the DC, Model 3 visuals with no slowdown , stunning textures and lighting effects
REZ- Area 1 and 5 are just some of the best shooting levels ever found and classic and imo the 2nd best game SEGA made in their history
ECCO - Just so relaxing to watch and play
D2 -Me my best mate and his brother playing this till 3AM over Christmas 1999 , where we made a drinking game out of the hunting section , Miss a shot hand over the joypdad and drink 2 fingers worth Larger from the can. truly brilliant times
Shemue II - Disc III (the rooftop section) and then the simply incredible so spiritual disc IV .
JSR - The most SEGA game ever made, so cool, so good and so, so SEGA (can only hope that SEGA will show it's face again oneday)