I don't understand why anybody would buy Sony products after they put trojans on their CDs and started installing rootkits on people's computers.
What would it take for you to stop supporting Sony? How much worse could a company get?
I rarely buy CDs and wasn't affected by the rootkits. Maybe things would be different if I had been.
The reason I'm tentative to say, "I wont buy another Sony product again," is that Sony seems to be everywhere. For example, Sony had a part in the development of blu-ray. I don't think I could honestly say I'll never buy a blu-ray (again).
They also make a lot of tvs and related tech (blu-ray players). In that case it's easier to avoid Sony since there should be quality competition. Still, it might be hard to pass up on a deal (i.e. recent refurb Sony blu-ray player for $100) because of the manufacturer.
I bought a ps3 because of Valkyria Chronicles. There also seem to be many quality exclusive titles, more so than what the 360 has (I don't count stuff like Mass Effect since that is available on PC). Nintendo seems to be Nintendo staples (Zelda, Mario, etc.) and a bunch of junk. Based on games available, my preference is ps3, wii, then 360.
I'm not about to stop buying ps3 games either, which is supporting Sony, even if indirectly.
Eh, I'm just rambling now. To try and sum it up; for me to stop buying Sony products (ignoring blu-ray) there would have to be no tempting games on the playstation platform. Alternatively, the options there could be less appealing than what Microsoft and Nintendo offer, or if my interest in gaming waned (it's not particularly strong right now) I would have an easier time avoiding Sony.
Honestly, if Valkyria Chronicles returns to the playstation I'd be quite tempted to buy it.