Even a newby can be confident in their quilting stitches. If your stitches are nice and even I would go with a contrasting thread color. Here is an example of a yellow variegated 100% cotton 35Wt quilting thread on black. Please disregard the blobs of cat hair this was taken while quilting so I had not yet de-haired the quilt. [ATTACH=CONFIG]488634[/ATTACH]
the higher the contrast and heavier weight, the more the stitches will show. For example if you opted for red in a 50 wt they would not show as much. I don't think I would use black thread as you will just about go blind trying to see what you are doing. Plus as Tartan stated, you want all your hard work to show. I like the idea of a gold quilting thread too, but not necessarily metallic.
As far as where and how much to order. I barely put a dent in a 500meter spool to hand quilt a 75 x 75 so one 500M spool should be ample. Where to order depends on what thread you want to use. I love Valdani quilting thread (used in above example). If you google it you will get loads of places to buy on line.
Red rock Threads carries many different threads. You could try them. here is a direct link to their handquilting thread by Superior
http://www.redrockthreads.com/superi...r-treasure.asp
But they also carry loads of other brands, including Valdani, but only in the 50wt which I prefer using a heavier weight for hand quilting. With thread, the lower the number the heavier the thread.