Feh.
Face it, the appeal of TV theme songs is their familiarity. You know every sound in your favorites. You won't find any of that here. Some of these aren't even close to the originals. A lot are performed on cheap, lifeless digital synths. All of them sound like tired run-throughs of the music. There is no apparent interest on the part of the performers, so why should any listener be interested?

Two tracks I really like
The Mission Impossible theme is performed well.
The Fireball theme is actually much improved on this version. I prefer the orchestra and the vocals over the original.

Quantity Over Quality
As a musician myself, I know too well that one of the most important ingredients in ANY performance (live or recorded) is passion. The recordings here generally lack the same passion and sheer drama of the originals. Much of the instrumentation has been reduced to a cheezy, thin, plastic synthesized replica. The performances are simply a watered-down lackluster version of the classic originals. If it were not for the sheer volume of tracks compiled here, I would have rated the comp only "one star".

Mediocre
The sound quality for this collection isn't much better than the samples offered by Amazon.

One Hundred Greatest TV Themes
I have watched almost all the shows that are on these 4 cd's. Many were made before I started watching TV. Most I've seen once or twice before.