If it will be in fact Half Life 3 (running on a brand new engine) then count me in. There's no way that 5-6 hours long Episode 3 would take more than 2 years to make.
I like the link established between Portal and HL. I think it was a smart choice. I really hope that in HL2E3, we learn what the G-man really is. We've been waiting like 3 years for HL2E3... a porject that they said would only take 6 months to develop. This better be worth the wait... im sure it will be.