I have serious AC questions. Help. Powervar?

I have been having some equipment problems, that I believe is due to AC power problems in my house. Most notably, my Perpetual Technologies P-3A cuts out very briefly when I flip the bathroom light-switch. It almost sounds like a skip in the disc. It started after I sold the Monolithic Sound power supply. Also, I own a Innersound ESL 300 amplifier. Sometimes, during bad weather (usually just before we will experience a power outage), the transformer begins to hum.

My main question is: will a power conditioner rectify this problem? I am interested in spending between $200 and $300 dollars. The following pieces have perked my attention: Monster HTS 3500, Adcom ACE-315 or ACE-515, the Powervar 1200 (this really appeals to me), and the rotel.

My other equipment is as follows:

Krell KRC Preamplifier
B&W Matrix 802 series 3
Sony X-77ES Cd Player
Perpetual Technologies P3A
Innersound ESL 300