You can't go wrong with M&K. I recently bought the 750 THX select system minus the sub. I opted for the Definitive Super Cube 1 since my dealer didn't have the 1250 sub in stock and would've had to been ordered.
The 750 system is VERY popular. It offers a very wide listening stage and is a little brighter than the s-150’s; however, many people prefer the brighter sound of the 750 system over the s-150. I would describe the sound as "Live". Even if the prices were equal, I would choose the 750's over s-150’s. The s-150's sound awesome when everything is ideal. They're true monitors. The mix, the equipment, and the listening environment all have to be perfect.
As a testament to their sound reproduction, I was watching Monsters Inc. while the cable guy was installing VOIP in my house and he couldn't stop watching the movie. He said he had seen it before and disliked like but for some reason, it was catching his interest. I asked him if he saw it in the theater and said no. He saw it at home with is little brother. He was about 20-22 years of age. It was the sound; he was installing VOIP in another room. I caught him standing in the hall watching the movie like 10 times.
The speakers will set you back for about 2600 which are not bad when you think about it. A good computer will set you back 4-5 grand and be outdated in 6 months. They carry a 10 year warrantee so you have piece of mind. I was even told they will honor their warrantee after that period. That's how much they stand behind their product.
Perhaps I can save you some time and recommend to you what I bought. I find it an excellent compromise between quality and price.
M&K 750 THX Select system minus sub
Definitive Super Cube 1
Denon 3805
Denon DVD 2200
The 750’s only come in a vinyl wrapping, if you want wood then you have to move up to the 850 system. They come with an upgraded tweeter than sounds smoother. The tweeter in the 750 system is the same as in the S-150.