In search of online music

I've decided that I've finally come to the point in my life where I want to find the right online music service. I have drafted a list of requirements heretofore:

1. Open format. No DRM. MP3 or OGG for me, please. I want something that I can listen to on the computer, on my mp3 player, or whatever, and that I can convert to new formats as new innovations come along. I don't want PlaysForSureTM, I want just Plays.

1a. (corollary to 1.) Everything has a price. I don't want anything for "free". Things that come for free on the internet are usually lumped in with some pain in the posterior spyware, adware or crippled terms of use (see above DRM note). I want to pay a reasonable amount for music, not get it for free and pay in other ways.

2. Buy what I want, when I want. No stupid 'subscription models'. I want to buy nothing for six months and then splurge out on half a dozen albums, without fretting about whether I have exceeded my monthyl download limit, or whatnot.

3. Range. I want a service that has what I want, which is typically mainstream/obscure requests such as a cover of Observatory Crest by Mercury Rev, or that song by Regina Spektor which has got stuck in my head. I don't have the time or patience to scour mp3blogs or P2P services for this stuff, I want to pay for it so I can find it without messing about.

4. (optional) Reputable seller. I'd prefer not to entrust my credit card details to a borderline illegal service which may turn out to be affiliated to organized crime. As a minimum requirement, I'd like a service that does actually accept my credit card, rather than is rejected by the CC service for whatever spurious reasons the pair of them can come up with.

So my simple question is, does such a service exist? All of the ones I can think of seem to fail on one or more of these points. The point being, until the music industry can sort itself out to meet these fairly minor requirements, they will lose my custom, and I'll go back to obtaining my music the old fashioned way: by buying up cheap secondhand CDs on Amazon marketplace and then ripping them onto my harddisk, just like my grandparents used to do...