What to wear for a professional conference?

I have a national conference coming up and I can't figure out what to wear. It's a professional meeting that occurs annually.

In the past, I presented at these meetings so typically wore a suit. This time, I'm not presenting (which makes it more fun) but am at a loss as to what is appropriate attire. I'm going to be there for 3 days.

Should I wear a dress shirt, slacks and tie? Would I need to wear a blazer with this?

Would a blazer, white shirt, and nondistressed jeans look too casual?

Also, what color blazer is appropriate? I'm assuming at this time of the year, I should go with a cotton light grey?

It's a cardiology conference (I would say large, thousands?), so tends to run on the conservative side. I would say fashion isn't a huge focus, if at all, so being comfortable without sticking out is the key.

Hm, the more I think about it, I guess I'll go with dress shirt/tie/slacks +/- blazer. Is light grey the best? My only hesitancy with grey blazers are that all my dress pants are various shades of grey and I don't want to look like I'm wearing a mismatched suit.

I guess denim wouldn't make the best impression, especially for networking purposes.

Yeps, ACC in Atlanta this upcoming weekend/week. I figured denim would look bad...

In the past, I've always worn a suit but was hoping to avoid it since I'm not presenting this time. From what I recall from past conferences (mostly AHA), most people wear suits although I never really paid that much attention? I'm trying to get away with not wearing a suit, while not looking too out of place.