Hey wahine-
Since Tri is mainly what you use it for I'd consider going with tri geometry. Someone somewhere posted an article about the benefits of tri geometry in the long run. And I must say that since I've started riding tri specific I run off the bike much better than I used to (last weekend notwithstanding).

Is the green giant a road bike? If so I'd consider fixing her up as your hill bike, and then going with a tri rig. There are some good deals out there on last years models as well. I know my bike (QR Seduza) was 3k when I bought it last year and the 06 model is now down to 2k. So that might also be an option. Do you have access to any good tri shops near you? I'm lucky because I have tri sports a couple of hours to the south. Yeah it's a 2 hour drive, but when I was looking for a tri bike that was the place to go. Most selection and best fit. I could throw out there a million brands that *I* like, but bottom line is fit. ESP in a tri bike where you will be in your aerobars for a looonnnggg time.
But just cause I like oooggling over bikes, these are my favorite brands.

QR- cause that's what I ride and she fits like a glove

Elite- small company from the east coast. Great service and sexy bikes.

Kuota- OH MAN! These are just plain sexy! Norman Stadler should have been put in jail for bike abuse at kona in 05! (he couldn't change his tire so he threw a tantrum and tossed his bike in the lava).

Orbea- See above.... Actually I mostly like their road bikes, but MAN are they sexy!