I must preface this with the fact that Revolution Power is a Furman dealer - that said, I give the opinion that the Furman M-8x is a good entry level piece with Furman "standard level" power conditioning. It is a rack-mount unit. The basics are there, but I would reccommend that if you can stretch the budget, go for the PL-8C or another of the PL series or, if you like a bar style that can fit behind a cabinet, try the PST-8 or the PST-8D.
The PL and PST-8 and above have far more advanced power conditioning in them. the power conditioning components are non-sacrificial like MOV's, and you have better line filtering, better surge protection, and high-voltage shutdown. The PL and the PST-8D (and 10-D) have isolated banks for analog and digital. blacker backgrounds, help eliminate ground loops and buzzing etc.. Just a better bang for the buck I think.
The AC-215 mentioned elsewhere recently is also a good choice.
Furman conditioners are constructed with sound quality in mind.
There are many good manufacturers of PC equipment, but for someone on a budget, I think these are very difficult to beat.