In general I find security suite programs to be a complete waste of time. People want a one-stop solution that they can just set and forget, and unfortunately security doesn't work that way.
The more layered security is, the better, and that means not having a bunch of security solutions all from the same company. In any other instance I can think of, I'd say code reuse is a good thing, but when it comes to security... Suppose there's a bug in that common code that someone can use to topple the entire suite? I've heard anecdotal stories to that general effect too. Someone is an IT admin at a company, and despite having these security suites installed, someone keeps cutting right through their defenses as if they weren't even there. They switch security programs, and immediately the intrusions stop. If you have an AV program from Vendor A, and a firewall from Vendor B, and maybe some other program from Vendor C, then even assuming a would-be ne'er do well knows how to compromise Vendor A's products, they still have to contend with B and C's products.
So, the reality most computer users (Mac or PC) don't want to face, is that THEY are the weakest link in the security chain. Also THEY are the ones who have to step up their efforts, because there is no magic program out there that will protect you from your own dumb self. You want to just waive everything right on through your firewall without even bothering to check into the program, the firewall will do that just as happily as it would block those same programs. You want to download a bunch of pirated software from suspect sites, and ignore your AV's warning about potential malware, it won't somehow still magically prevent you from being infected. Plus, I have yet to find a single security suite that can tackle the social engineering angle.
A very recent case in point: http://forums.cnet.com/7723-6142_102-564224.html
Someone calls up pretending to be from Microsoft or some other company, gets you to give them access to your computer, then proceeds to do a bunch of unwanted things which you allowed to happen. Or there's the classic Nigerian 419 scam, which people STILL fall for in droves, and there are pyramid schemes still going somewhere I'm sure about how you send a couple of people $1, and then put your name on a list so people then send you $1. Security software will not help gullible people be any less gullible. In fact, it'll probably do the opposite, making them THINK they're protected when they're really not. Which is why when those ne'er do wells finally catch up to Mac OS X, it's going to hit most Mac users especially hard. Everyone who's been sold on the false promise of Mac OS X being immune to this sort of thing. Which isn't to say Kasparsky isn't scaremongering when he says Mac OS X's security is decades behind Windows... He's just trying to drum up some business given it's only been the last year or two his company arrived at the Mac OS X party... But there's still a nugget of truth in there kind of deep down. A lot of Mac users are living in a fantasy-land where they think that the simple act of using a Mac makes them somehow immune. That will be a rude awakening.
So I commend the efforts you're making to try and keep up on these things, but I'd say your focusing in on suites alone is a misguided one. You want to spread things out a little. It might be a bigger PITA to maintain, but that's just how it goes. Security and usability are on opposite ends of the spectrum. The easier something is, the less secure it is on the whole.