Absolutely. A lot of the other passive-aggressive suggestions about getting physical with your 'intruder' are as "rude" as standing too close. (I'm using quotes because personal space is cultural, so being too close -- in and of itself -- is not rude.)
Just politely ask people to give you a bit more space.
ITA - while I am one of those people who likes my bubble too

, so I definitely see this from the point of being intruded upon, and of course, I tend to get a bit defensive in such a situation. I typically use the Glare of Death
TM, and I think the only thing I have actually said is "oh, excuse me" and moved
into the space I want the person to move
out of (ex. between me and my pin # or me and my pharmacist) and if I accidentally bump into them in the process, I justify it by saying they shouldnt have been there in the first place (this is only extreme situations, like the lady that would not move from the CC machine at the store bc she was mad at the clerk and didnt want anyone else in the line to check out-definitely not a cultural thing).
But a couple posters have mentioned how they are working on issues with crowding/it's a cultural thing, so I guess I will take it as a lesson learned from the good folks on e-hell...