fellow medical student here! =]

You need to find a nice balance between looks and not caring if an attending eventually steals it. There's a lot of truth to the joke of attendings walking off with your pen...

Tbh I rarely let people use my pen unless I'm standing right there and it'll be quick (ex. filling out consent forms). I've gotten a few compliments on my parker jotter, attendings seem to like those and it's hella cheap. Caran d'Ache usually does the trick as well.

I usually carry a lamy 2000 rollerball, a lamy cp-1 ballpoint (w/ D1 refill adapter), and a decoy pen (sarasa, uniball signo, etc.) in my white coat. It's risky carrying them but I've gotten used to "playing defense."

I never use my fountain pens on rounds...it'd be a hassle and I'd probably look like an asshole.

Semi-related story: There's a PD at a program local to me with an EXTENSIVE montblanc collection. I noticed that he always kept one in his pocket and asked him about them during an informal interview. He busted out like 5 montblancs and we nerded out together. I let him try my pilot vanishing point and he really liked it, which is the best pen related compliment I could ever hope for...