A personal favorite of mine, as is Grand Prix Legends... when I need a break from WWI.
If you loved RB3D back in the day, then you might also remember Panzer Elite. This was yet another fantastic, detailed game loaded with realism and depth, however, suffered from a poor graphics engine (even for it's time) and lack of historical accuracy.
But... real in a supportive community as WOFF, RB3D and others have and you get PP2-x.
Take a look. It's still going strong with lot's of new/updated vehicles, sounds, graphics. It's a blast to play even for today's standards. Sometimes simple is just better.
http://combatace.com/topic/84534-panzer-elites-new-look-pp2-x/