What is Rooting, and Why you should or shouldn't care? (Updated 28-10-11)

I used Super1Click 2.1.1 to root my GT-i9000M last night.

Maybe he/she needs to get the newer version?

I'm using a notebook,too. Vista, Ubuntu and Linux Mint on it.
To flash a ROM:
- your phone should be SIM unlocked.
- you need to use the 3 button combo.
- rooting: you should flash the Speedmod_k13E.tar as PDA in Odin.
To get to download mode use the ADB method!

Ok.

I have been searching the 'Net for two weeks trying to find out how to root my phone.  I think I have 'found the place'.  I certainly hope so.  Here is what I think I know:

Samsung Galaxy S 4G from T-Mobile USA

From SETTINGS/ABOUT PHONE
Model SGH-T959V      <<<<<<<<<<<<???????
Firmware:  2.3.6
Baseband T95VUVKJ6
Kernel 2.6.35.7-T959VUVKJ6-CL694130
Build number Gingerbread.VUVKJ6

From stickers on product BOX:
Samsung Galaxy S 4G
8 GB expandable to 32GB
5 megapixel camera
SAM T959V GALAXY S 4G REFLEX SILVER KIT
Kit SKU 610214625717
Handset IMEI 357982044973525
Untitled tag 000000610214625717
Untitled tag RS 170-6157
SIM Serial # 8901260531589381839F
BAN number 245687643
TGT 170-6157 Made in China
Model #: SGH-T959HABTMB   <<<<<<<<??????????

I am VERY new to Smartphones.  My main goal is to root so that I can uninstall bloatware .. though the other advantages are also desireable.  I would also want to know how to UNroot in the event that I would need to send it back to T-Mobile (or would it be Samsung?).  ALSO, I read somewhere that rooting a phone CAN prevent 'online' updates ... from Samsung or 'whoever'.  By that, I mean (for example) when/IF an upgrade from Gingerbread to Ice Cream Sandwich is ever 'offered' .. I would certainly like to have it ... I would think .. though I read about that being possible through other means already.  More confusion .. actually.  

Back though, to priorities .. get this phone rooted and get rid of a load of bloat .. yet be able to get 'official' updates/upgrades .. which I assume means I will have to be able to UNroot.  I dunno .. to be honest.

Other issues I have read about ...

LAG ... but from what I understand this does not apply to Gingerbread as it uses EXT 2 or 4 ... can't remember which at the moment.  Maybe LAG does apply .. dunno .. more confusion.

Fashing ROM.  From what I have read .. not sure what that would do for me.  I THINK I read that 'flashing a rom' can result in a ROOTED phone .. but at the same time .. changes a lot of other things.  I sort of don't think doing so is something I entertain ... more confusion.  I also 'get the idea' that in order TO root, I will need to flash ... and I am not too clear on what the result of that is ... more confusion.

So, .. here I am .. hoping to uninstall some bloat .. and do not know what my next step is.  Obviously it would be to go to a thread that tells me what to do next .. but for some reason .. I don't think I am quite ready for that.  Still too much confusion.

For what it's worth, I have both an XP 32-bit and a W7 64-bit machine available to 'do the deed'.

Thanks in advance to anyone who can help me move forward.

EDIT:  Did I post in the wrong thread?  If so, please let me know .. and what to do aboutit (repost, have thread moved by moderator .. whatever).

thanks ironsingh, knew nothing then knew something , i may go ahead with making these options available , i love my galaxys2. is odin pretty solid ?