depends..
D/P/Pt have better late game content
HG/SS is terrible late game.
EDIT: Point; if you're into making new games after the Elite Four and such, get HG/SS. If you're into late game stuff like collecting all 493 and making different teams for the Battle Tower/Frontier, get D/P/Pt. Preferably Platinum because it pretty much iron out quite a few things wrong with Diamond and Pearl.
Pixel Art can be fun.







