Dell OptiPlex 755 SFF and Multiple Monitors

Hello,

I recently purchased a second user Dell OptiPlex 755 SFF (C2D 2GHz, 2Gb RAM, 80Gb HDD).  I also no possess three monitors (1x Dell 19", 2x IBM/Lenovo 19" - all have the same maximum resolution of 1280x1024).

I'd like to know the most practical and cost effective way of running these monitors with this machine simultaneously.  I looked into the Sapphire Radeon HD 6450 FleX, however that would not fix in this system (due to the second DVI adapter plate being where no slots are available).

The intended use is: Two monitors that will be used for gaming, audio/video processing/editing and one for general-purpose applications (such as web browsing, checking email, etc)

Which of the following would be most practical:

a) VTX3D Radeon HD 5450 (using the DVI and HDMI ports) + XFX GeForce FX 200 (VGA-only)

-or-

b) ASUS EAH5450 (using all three ports) + Sapphire Active DisplayPort to DVI cable

Or any useful alternatives - graphics card + 'accessories' suggestions only please - I'm not considering upgrading case, etc.

Kind Regards!