Honestly, I wouldn't worry about it a great deal. You have to go to some effort to really build up static charge, like wearing polyester socks and rubbing them on a carpet for ages...
Lay out some old cotton t-shirts or something on the desk, and put the hardware on that if you're going to run it outside the case. Additionally, you can make sure to touch something grounded before you start to poke around on the mobo - e.g. a radiator pipe, or your chassis if it's still plugged in. Also, try and avoid wearing a fleece, or something man made. Get an anti-static wrist strap from Maplin if you're really worried : http://www.maplin.co.uk/search.aspx?menuno=12497
I've worked in various electronics companies in my time, and I've NEVER heard of an ESD-related board/chip death, even with people often being pretty lax on the precautions. TBH, the only ESD-related death I have heard of was because of the ESD precautions! Some total n00b decided to store a whole bunch of backup batteries with their pins pushed into some anti-static foam. Over time the batteries slowly discharged, despite the foam having a very high resistance. This meant that boards we were putting together were going out with half-dead batteries in, which was not a good thing...