I'll answer those personally, as a 360 owner:
1. Exclusives
- This goes a little deeper than just exclusives unfortunately. Excellent titles like Orange Box were simply ported over by a studio other than the one that produced the game and the result was a poor experience for PS3 owners. The EA games last year for the most part, even though they were to be similar/identical experiences ended up being far from that (360 60fps vs PS3 30fps). Exclusives are one thing, but these are big problems, and hopefully they are over with (DMC4... install stuff aside, is a good sign). Sadly, these are likely a publisher's fault, not the makers of games. With the post-November sales of the PS3 as good as they have been hopefully the system will receive a bit more respect and money thrown at it as it becomes clear that money will be returned via sales.
As far as actual exclusives, we'll see how they continue to play out. I believe the Halo series is over? I assume there will be a DMC5, will that be multi-console? Having not played some, I know there are some good ones out there on both sides... so would depend on your playstyle which hasn't really been addressed here.
2. Blu-Ray.
- You've mentioned this a number of times, but you don't want to connect via HDMI, so certainly not a super priority.
3. Better online play
- This really is dictated by the producers of the games. True, the 360 has a better more seamless online component, but if you just want to play COD4, you can surely log in, hit quick play or whatever, and you're in a game. From there I don't expect much of a difference, if anything the Playstation has a leg up since their online games generally support a few more players. This can be a good and a bad thing depending on the game's design. If, while you are playing a game, you want to be able to check on what friends are doing, chat or send messages with them, invite them to your game or invite them to yours, even when you're in different games, then this is something only the 360 offers.
Is there any other part of these systems that can help you make the decision? Online content perhaps? I'll let someone who has one go into what the PSN offers, but the 360 currently has more than 100 'Arcade' games, all with a trial version, most purchasable instantaneously for a few-to-several dollars. I expect demos of many titles are available for both systems online, and I believe Sony now has or is unveiling a video download service, but the Live Video Marketplace certainly has more deals with content providers at the moment.