Best DirectX 9 games?

Most all the UE1, UE2, & UE3 Unreal Engine Games should work fine.

Bioshock 1 goes well on low end systems

Killing Floor, Rust has DX9 version, Borderlands series, Telltale point&click games, Far Cry 3, F.E.A.R. 3

One that comes to mind right away would be GTA : San Andreas, if I recall more, I'll edit. ^.^

It would also aid if you left a category of games around, like perhaps Strategy/Adventure and so forth. :3

Man. there is a lot of games ;)
Dead Space 1-2, Mass Effect 1-2, Resident Evil 4-5 etc.
Many great indie-games, that no need too high systems: Invisible Inc, Mark of the Ninja, Dungeon of the Endless, Axiom Verge, Hyper Light Drifter and more, and more.

play clive barker Undying

its good dx 9 game

still unmentioned: metro, bioshock 2, tomb raider, torchlight 1 and 2, fallout 3, far cry bd, crysis, half life (all), civ 5, dirt 3

Thought I'd bump it again, since it's a new year, the sale has ended and more new games have come out with it.

Skyrim

Saint's Row: The Third have an option to choose the DirectX, if I'm not remembering wrong

Warband works well. There's an option to use Directx 7 too.

I know that feel bro, i'm one of those aswell. This are the games that i'm playing now:

-Awesomenauts
-Beat Hazard
-The Binding Of Isaac Original & Rebirth (Be aware, the new dlc Afterbirth+ doesn't work on WinXP, dont make the same mistake)
-Borderlands 2
-Castle Crashers
-Crypt Of The Necrodancer
-Darkest Dungeon (:3)
-Darksiders
-Dirt 3
-Dont Starve & Dont Starve Together
-Doorkickers
-Downwell
-Duck Game
-Enter The Gungeon
-FTL
-GRID
-Gunpoint
-Half Life 2
-Hotlime Miami Series
-How To Survive
-Intake
-Keep Talking And Nobody Explodes (awesome game as a couch game -or online couch- with your friends)
-Killing Floor
-Left 4 Dead 2
-Luftrausers
-Not A Hero
-Nuclear Throne
-OlliOlli
-Paladins
-Retro City Rampage
-Risk Of Rain
-Skullgirls (It can look like on of those ecchi games, but actually, it's my favorite fight game, really well done mechanics)
-Spelunky
-Sunless Sea
-Super Meat Boy
-Super Sanctum TD
-Teleglitch
-Terraria
-They Bleed Pixels
-This War Of Mine
-Titan Souls

Posting here your rig should work a little.

GTA - SA and install SA-MP multiplayer mod ;)

Don't forget about XCOM