As DCR pointed out, you indecisive would-be full-size 9mm buyers always seem to forget the Hi-Power. It is the 1911 of 9mm's. That would be my first pick too. Other folks besides Browning have made Hi-Powers, so they don't need to be super-expensive. We have a Charles Daly that is US-made, and is just fantastic. It cost us $350 new a couple years ago. Cabelas was closing them out.
However, I'll give you the benefit of the doubt and assume you already considered and discounted it. In that case, let me know what your primary use is. Since you said full size, I'll go out on a limb and assume you're not going to carry it. (correct me if I'm wrong) If that is the case, there are my picks, in order of preference:
- CZ SP-01
- FNX
- FNP
- Storm
- P99
- STI
The SP-01 has the longest sight radius and is the heaviest. It also has the slide rails which run inside the frame rails, so will probably be the most accurate. CZ75s are exceedingly comfortable. Can you get an SP-01 that can be cocked & locked? If so, that would put it on equal footing with the mighty Hi-Power.
The FNX, FNP, and Storm, I consider to be equal, and style is probably the biggest factor between them. The Storm I shot was in .45 ACP. The trigger was great, and it was very comfortable. I'm luke warm on the futuristic looks though.
The P99 is my favorite gun of the bunch, but is probably inferior to the ones above it in the list for pure target shooting. You see, it is smaller and lighter than them, and has more perceived recoil. It has the best trigger I've ever experienced on a striker-fired pistol. I owned a 1st gen. one of these, and I miss it sometimes. The trigger breaks very cleanly, but only in the last couple mm of travel.
STI - No experience with it. Is it a 9mm 1911? If so, yuck. They shoot well enough, but are not pure of heart. It is like if a tiger went out and raped a lion, the offspring would be a feak of nature; an red-headed stepchild; an orphan. I've shot 9mm 1911s, and the recoil is quite soft, and they're quite accurate. But the idea of it really turns me off. It makes me wish they'd put some effort into making race guns out of Hi-Powers. They could be just as popular as 1911s.