I purchased this set
http://www.woodline.com/p-1766-30-pc-professional-set.aspx
and have been pretty pleased with it. I thought that it would be nice to have a good basic assortment, and then replace them as they get worn out with higher quality individual bits. That way I'd end up with nice bits for the frequent uses, and serviceable bits for all of the occasional uses.
I've been using the set for about 4 years - have used about 3/4 of the bits in the package, some more than others, but none of them are dull or worn yet, so I haven't replaced any.
I think the Woodline stuff represents a pretty good value. Not top quality, but affordable, and good enough for a weekend warrior like me. As far as quality of cut, apparent build quality, hardness/durability, etc. I'd say that they're about on par with the couple of Porter Cable brand bits I had prior to purchasing the set. Plus - they come with a lifetime warranty.