However its very expensive for what it is and isn't going to allow you to play modern games due to its low performance.
If you just want to watch movies then its fine, if you want to play games then buy a console or save up and build yourself a PC.
I strongly disagree. Many PCI-E video cards will work just fine via a PCI-E x1 slot. You are not limited to choked Low Profile type PCI-Ex1 cards, since the large case of the Poweredge accomodates adapters from PCI-Ex16 to PCI-Ex1.
The server admittedly is old, and gaming would be terrible via the 1 lane slot.
It is possible to seriously slow down the PE800 by using the sole PCI slot due to tied resources now limited by that super slow slot in use.
However, older PCI-E video cards cost less than the shipping, if used, on ebay, and a slot adapter can be had at camera2000_com, or a ribbon type adapter is easily found.
I can't say what newest highest powered card will work, I suggest searching Dell.com forums for 'Poweredge video card'.
Installed is a Sapphire HD3650 256mb right now.
I suggest a larger card requiring a separate power connector. Dual displays with separate content no problem then. I did this with an older card.