Yep, true fun. How to set sensitivity to different values for On Foot, Land Vehicles, and Air Vehicles? You can do so manually by editing files.. I will cover that tomorrow when I can sit at my gaming/music computer and take some screenshots and such. For now!

http://www.evil-minds.com/index.php?option=com_content&view=article&id=8&Itemid=2
That is a link to "Evil Minds Configurator." Personally, I prefer to dig in and understand what my cfg(s) is/are doing, how they work, etc. Tomorrow, the manual way to accomplish this!

AWESOME! Tanks make me rage x2. I play with really low sensitivity so turning the tank takes 3-5 mouse lifts.

Here we go!

First, you will need to find your BFBC2 folder where all your settings and such are kept. Typically, this will be in "My Documents" (on Windows 7, unsure about others) folder.

In the BFBC2 folder, you will have several files, including "GameSettings.ini" and "settings.ini"
Neither of these files has the settings we are after.. but, a quick note: in the GameSettings.ini file: right-click, select "Edit" and once open, scroll down a little, and you will see the line:
"ORIGINALVOFORENEMYTEAM="
If it is "=1" then change it to "=0" (zero). This will make your in-game languages for both teams English... but, foreign speakers retain the accent!!! So, you can still distinguish who is on your team and their team by voice.

Back to the fun!
Also in the BFBC2 folder is a folder called "input"
In that folder, there should be 4 files; "air.dbx" "infantry.dbx" "land.dbx" and "shared.dbx"

The air, infantry, and land .dbx files have (among other things) info on how your controllers operate relative to the game.. IOW, sensitivities! How fast your turret turns, how fast you turn when on foot (infantry), etc.

This thread: http://forum.ea.com/eaforum/posts/list/446923.page
Has info on setting your mouse smoothing, but also contains portions of what I am describing. Check that post first, and then come back here.

Welcome back!

BACK-UP YOUR FOLDER!!!
===================
Back up a copy of your BFBC2 folder and ALL of it's contents FIRST!!!
===================
BACK-UP YOUR FOLDER!!!

Okay.. if you read that first post in that thread, you should be familiar with the .dbx files. You should also have made this connection in your brain: The GameSettings.ini file contains your main sensitivity information; those .dbx files are settings that are RELATIVE to settings in the GameSettings.ini file.

What this means: Open your infantry.dbx file (right-click on it, select the "edit" function.. launches notepad with document loaded).

In your infantry.dbx document, scroll down a ways and find the "ConceptIdentifier">ConceptPitch<
section (like in that thread post). Then scroll down a wee bit and look for the line
GameSharedResources.MouseInputActionData
In that section will be the input parameters for your mouse; these are relative to the GameSettings.ini data!

In that section you will find a line beginning with:
field name="ScaleValue"
This is a multiplier value for your sensitivity for Infantry (on foot) in this case. Whatever your main sensitivity is set to, this value will be multiplied with it to derive your infantry (on foot) sensitivity. Sensitivity has TWO values however: Pitch and Yaw. Pitch=up/down, Yaw=side-to-side. This was for Pitch. To adjust Yaw for mouse use for infantry.. scroll down a little more, and find the "ConceptYaw" line; once again, this *announces* that the section following will pertain to Relative Yaw Functions, and since it is the infantry.dbx, this will (once again) be for infantry (on foot) use.

land.dbx= land vehicles, and air.dbx=air vehicles, such the choppers.

Warning: Yes, you might/will find seemingly duplicate sections!!! If you have trouble reading the XML stuff, find me (or someone else who understands this) in TS3 and ask. The XML sheets EA coded are actually structured quite well, which makes it (relatively) easy to read and thus edit. With duplicate sections, verify which ones are actually being used; some will have something like, "field name="Axis">IDA_Undefined
Any issues, post 'em or ask in TS3. If someone can create a more well presented write-up, I would gladly remove this jumble (mods, please feel free to delete this thread and start a new one with a better write up!)

I did not mention it, but obviously- perform this edit for each of the 3 main .dbx files (leave shared.dbx alone). I would suggest:

First, back-up your BFBC2 folder and all of it's contents!!!
Second, get your in game "on foot" (infantry) settings how you like them.
Third, hop in some land vehicles, and then air. Make notes on sensitivity- pitch AND yaw- while operating them.
Fourth, start with land vehicle adjustment. If you want the turret to spin faster, up the ConceptYaw section "ScaleValue", maybe try "=2" to start.
Fifth, fire up BFBC2, find an empty or friendly server you know you can try things out on without pissing people off.

Trial and error time.
I suggest trying ONE VALUE initially. Once you get comfy, have a blast.
Good luck!!!