I know that Steam for linux is on the way and have been seen a lot of games appearing in the Ubuntu Software Centre of late but my system lacks a decent graphics card and was hoping I could get some recommendations.

The desktop is a Packard Bell Imedia S1800 (or Imedia D3526 UK) with the following specs;

• Memory: 3.8 GiB
• Processor: Pentium(R) Dual-Core CPU E5800 @ 3.20GHz × 2
• The system lists the graphics as 'unknown', though I think its just an integrated Intel card

From what I can see there is a free PCI-E x16 slot.

Any advice would be great, thanks!