If have seen the relatively new Gel-Bot Bottle that allows for gel delivery in your water bottle (http://www.hydrapak.com/catalog/product2095.htm) and wondering if it is worth trying: Yes. It actually works very well and I recommend it -- and as someone who still rides a steel framed bike with downtube shifters I am not much into fads or having to have the latest whizbang gizmo.
I have both the regular one and the running version and I love them.
I concur! So convenient, and much better than fiddling with tearing open the packs and then figuring out what to do with the trash. My only complaint is that it's a bit hard to clean once the goo gets stuck in the mouth piece.
I have no idea what that gellato-robot bottle-thing is, but downtube shifters rule!
My ride is a 1992 Cannondale R600, which is actually aluminum, so I'm not quite as retro as you. Although, from looking at that avatar, it appears you've purchased a helmet in the past 10 years, so we'll have to call it even. ;-)
If anyone is interested in picking one up cheap, I've had one for about a year but have only used it once. I just prefer gel flasks. I'd part with it for $8 or for a beer or two at a happy hour. Just e-mail me: rdejonck at gmail.com