On my Marinoni, I've got one cage that came with the bicycle, and one cage that a friend gave me. I've no idea what brand they are or anything, but they've seemed to work for over 4 years now, so that's good enough for me. As long as they hold my bottles in place, I'm happy.
I like stainless ones as well-- the Salsa ones are nice, and the Performance ones on sale are nice as well.
As far as researching your bike too much.....no you're not. Most riders worry about the bike weight and the gruppo...but as long time rider, that stuff isn't important. Getting the right stem and saddle hight or important, picking the right saddle, getting good water bottle cages, getting a good tight fit for fenders, picking good a headlight and taillight (if you need them) and most of all, the correct tires.
It's all these little things that make a good bike. You're on the right path.
NO-ONE can overthink a bike project. It's just that you do need to make progress towards the final choices at some stage or another. It's like touring for me... half the fun is the dreaming and planning. Heck, I have an MTB project that has been underway for three months as I acquire bits and pieces for it. Of course... the frame, an alloy one, came from the local dump shop for $5 about nine months ago.
I digress... I have just bought (from ebay, where else) the Topeak Modula XL drink cage. This is the one that extends to take 1.5-litre plastic bottles. I'm figuring that on long tours and randonnees with fair distances between services, this will be handy.
Up to now, I've used cheap and generic bottle cages from LBSs, alloy ones. I am, however, beginning to hate the grunge they leave on the bottles and want to go stainless steel... but they are difficult to source here in Australia by internet/mail order.
Just as yet another digression, I insert my bottles in cotton socks (baby ones) to (a) help protect the bottles from wearing against the cages (b) stop the bottles from going black and (c) keep the bottle contents cool by soaking the socks in water.
I've got a vast assortment of cages on the 12 or so bikes I maintain for myself and my family. Some I bought because they were the cheapest. Some came on used bikes I bought. None are carbon fiber; they're all steel or aluminum or plastic. They all work fine. When I built my wife's bike she wanted a black and red color theme. The frame was black so I bought shiny red plastic cages. They look cool and she likes them. For my latest project I went for the "color scheme" thing with the cages. It's also a black and red frame and there's a lot of red where the cages will be, so I bought black ones.
I can't believe I'm going for color-coordinated. Have I found style in my old age?
Trek 630 • Jamis Quest • Bilenky Tourlite and various others
BBT, I'm with you. With all of the styles, colors and materials of cages out there, it's hard not to go with the asthetics. That said, I bought some (fake?) Specialized carbon cages for my road bike and they leave a little something to be desired. Not enough to change them, but when I put cages on my most recent bike, I went with Specialized (shiney) plastic cages of a slightly different design which hold bottles much more securely and look even better.
I still have aluminum cages on my mtb as the bottles get dirty and filthy anyway and it makes no odds as to whether the aluminum marks them up or not.
I have a 10ye olf cage by Elite made from nylon-reinforced plastic. it is soft and deformable so can take a lot of bashing around, especially at airports. It circles the bottle completely so is suitable for use under the down-tube. I have lost 2 bottle and suffered one cracked cage from the extra stress of DT positioning.
The only downside: I cant find another one like this.