I think the 200mm "L" lens is one of Canon's best bargains, but I don't think it would be the correct lens for portraits, especially on a 30D with an APS-C sensor.
If you're looking for a bargan lens for portraits, Canon's 50mm f/1.8 would be the best bargain. If your budget allows, the 50mm f/1.4 gives you a better lens. If you like a little more distance for portraits, Canon's 85mm f/1.8 is a fantastic lens and one of my favorites. It's a little too long for indoors, but works great outdoors.
Also, if you can stretch the lens a little farther, the 17-55mm is a terrific portrait lens. I use it a lot for indoor shots. It's not as fast as the primes, but is probably more versatile, especially when shooting with a flash.
Here's a shot of an unidentified person with the 50mm f/1.4
and one of my granddaughter with her ribbons from a horse show
and here's a few with the 85mm f/1.8:
one of my other granddaughters:
and one of her brother:
This one was taken with the 17-55mm outdoors - no flash
Hope this info is useful,