I can testify that oregano and thyme will spread to fill any space available, and beyond. One two-inch pot of thyme I planted in my garden now fills a space nearly 3 ft by 4 ft, and is trying to crowd out everything beyond that. My oregano plant is about 3 by 3 as well, and has blown seeds up to five feet away that I've had to dig out when they sprouted.

Basil will stay very tidy if kept pinched - I have six of them this year in a 2 ft by 2.5 ft space. It is annual and won't over winter. Keep the flowers pinched off and you can continue to harvest leaves over the summer.

Parsley is a biennial; the second year it flowers, sets seed, and dies, but the seeds germinate easily so it's not hard to keep a continual patch of it.

I just got my first Nepeta this year, and one thing I do know from studying varieties is that the size and height vary a lot by variety, so how much space you need for it depends on what you've got. I don't know how aggressive it is about spreading, though I'm about to find out along with you :)

I have not grown Lemon Balm or Borage, sorry.

Oh boy, I'm fighting my lemon balm this year.

Lemon balm will get huge and take over as I'm discovering. Three years ago I bought a small plant and put it in with the lettuces and spinach. I'm not very good at harvesting it before it flowers and it grew about 2 feet high and wide in a mounded shape.

The next year I split it in half and moved one half to another part of the yard. Both ended up about the same size as the previous year.

This year I dug up the original part in early spring and moved it out of the veggie bed. That part is about a foot high and wide so far. The other part is already over the 2 foot mark.

The problem I am having now is seedlings of lemon balm that are scattered all over the veggie bed, outside the veggie bed in the rocks and even in a container of mint that is next to the veggie bed.

I was out taking pictures today and will try to get them off the camera later on but there are about 100 to go through (some from our recent trip out to Oklahoma).

I second Jnfr, Oregano and thyme do really well - I cover mine with pine needles in the winter. I haven't had a problem with either taking over though since we use a lot of both over the summer, mostly in marinades, dressings and pasta salads.

Some others that do well that you may not have thought of are:

Winter savory - excellent in meat dishes, spreads like crazy, the older stems are woody but gets new growth in the spring, and doesn't die back.

Burnett - tastes like cucumber, grows in a mound, gets flowers in the spring every year that I just cut off near the base and new growth as the summer goes on. I've never had it die back.

Dafy (another Jen)

Finally got the pics up

Oregano - Was cut back and covered with pine needles for the winter

Lemon balm - The first is the division I did last year that needs to be cut back; the second is the original part that got moved to a slightly shadier spot this year; the third is the seedlings that are coming up in and around the container.

Burnett - also needs to be cut back (see what happens when I leave town for a week)

Sage - This plant is three years old. I cut it back and dry the leaves every year in the late fall.

Dafy/Jen

Winter savory - 3 year old plant

Thanks Jens!
The info helps a lot and especially the pictures.
I'll have to check out the winter savory & burnett, thank you for the suggestions.

Maybe I should put the lemon balm out in the back where it can create an entire patch if it wants (and Dafy, it looks like yours really wants to...)

I had catnip in my old yard and it spreads like the lemon balm - EVERYWHERE!! Four years later, there were still volunteers - in my yard and the neighbors. It also attracted cats to my yard and my male cat started marking his territory...inside the house...but thankfully only in the plants that were near windows.

I found some cuban oregano - two kinds because they look nothing alike - and read that I have to bring a cutting inside for the winter. The variagated is the only one I've cooked with and OMG is it wonderful!! I'm going to try covering them with mulch, but will also bring cuttings indoors as I'm not sure I could find them again. I also bought Greek and Italian oregano and can bring some cuttings of all to the fall swap.