Apple Mac Pro 1,1 MA356*/A, 2 x Dual-Core Intel Xeon 2.66Ghz, 5GB RAM, 730GB HDD is this a good computer to have or is it old?

Sure, it will run Lion so it is still supported.

Be sure to get the original discs that shipped with the machine. It is worth significantly less without them for several reasons. The seller is obligated to either erase its hard disk or restore it to its original condition, and you need its original discs to do that.

You would need to purchase any OS that was not installed when it was built. $20 for Snow Leopard and another $20 for Lion.

Yes, the original Snow Leopard disc as a minimum. You will not be able to repair or reformat the hard disk, or reinstall Mac OS X without a System disc.

As I wrote, the seller is obligated to either completely erase its hard disk or restore it to its original condition before selling the Mac Pro.

You will also not be able to run Apple Hardware Test without the original grey system-specific discs that shipped with the Mac Pro. There is no way around this. Obtaining replacements from Apple can be difficult.

http://images.apple.com/legal/sla/docs/macosx106.pdf

You're welcome.

Used Macs without system discs are certainly usable... at the right price. They are most valuable to someone who already owns an identical model, and needs parts to fix it, or a spare.

I would not recommend what you proposed for someone's "first Mac" unless that someone is a computer geek or electronics nut. There are too many paths to frustration for everyone else.

If you want to save money, shop Apple's Special Deals page:

http://store.apple.com/us/browse/home/specialdeals

If you are a serious user buying in to the Mac Pro line today, you should start with a 2009 or later model if possible.

It is cold-hearted to say so, but as a new buyer you should think of the earlier models as "temporary", or "disposable". That is perfectly acceptable if they are being offered at appropriately CHEAP prices.