Went out this weekend in my 3/2 with boots and gloves. I was pretty warm but I tried taking my gloves off and quickly remembered why I brought them. The water was around 51F with air around 68F when I was out.
I mentioned on another similiar post...it all depends on the quality and style of your 3/2. Fairly new lightly worn wetsuip with taped and sealed seams you'll be fine down close to to 52-55 degree water temp (about where its at now in the mid-Atlantic)....a lower end 3/2 suit with flatlock seams, back zipper that lets cold water flush down your back....you'll freeze in anything below 60-62 degree water temp. Figure out the condition and quality of your 3/2 suit and then make the assessment.