Indyologist said:
Okay, okay. All female ogling aside (but hey, ya gotta expect that from me, guys)...
He is resourceful, intelligent, has a rapier wit and is, above all, vulnerable. Even though most of the scrapes he gets into is pure Hollywierd derring-do, he himself as a person is believable. That's what audiences liked about him, that's what spielburg liked about him, and that's what I like about him. Also, he's freakin' gorgeous. Sorry, had to put that in. You all made some excellent points.
Here's a nice quote from Spielburg:
"I always envisioned the character of Indiana Jones as a real throwback movie hero: a lover and a cad and a two-fisted hellion. In the early sequences of the movie, while he's teaching a class, he looks the picture of a well-dressed professor. But the moment he puts on his fighting clothes?his leather jacket and his hat?he suddenly is dressed also with half an inch of dust, and dirt around the cheeks and under the nails. And, unlike James Bond, he doesn't win every fight he's in. He gets to the edge of the cliff, and sometimes he goes over the other side. He doesn't necessarily survive every cliffhanger unscathed. That was one of the things I was determined to do. I didn't want this man to get into this kind of action and come away with white teeth and washed hands. Instead he comes away cut and bruised and battered and wonderfully in pain."