"grey" hulk was usually called either Joe Fixit or Dr. Banner - depending on who he was talking too.
It's the same guy though (Dr. Banner/original Hulk), just a different time.
First, he turned into a green strong and stupid giant when angry, and the weak scientist Dr. Banner when not. The 2 rarely shared any memories. The Hulk most ppl know.
His strength was theoretically unlimited, as he got stronger the madder he got. His only limit was his anger.
Then for a period of time (I think after another gamma bomb), his skin turned grey. Grey Hulk was not quite as strong as Green Hulk, but they were very close. But Grey Hulk fully retained all of Dr. Banner's memories/thoughts/etc. I think he was also permanently Grey hulk, and never reverted back to Dr. Banner. He was affected by day/night...and he think worked as a bouncer at times, because crime fighting just didn't pay. He also liked dressing up in nice suits, lol - he was entertaining.
Being a comic nerd alumni, I should point out that while the movie says Abomination is stronger than the Hulk...this is kinda true and untrue, lol. Under "normal" circumstances (ie: calm), Abomination is stronger. But as mentioned before, the Hulk's strength is theoretically infinite - directly proportional to his rage.
In the Marvel universe, there is nothing stronger than the maddest Hulk. Kinda like some of the members here on AM...except Abomination might be better looking, lol.
...waits now for all the PM's from hot chicks to come in who are impressed and attracted to my sexy knowledge ... .........crickets........