All about lenses

I say buy all the canon lenses they make and then it will satisfy your every need.

Buying Rebel and buying 2300$ EF dedicated medium fast zoom for "gatherings (e.g. Weddings)" just because you don't want to change lenses?
135L for crop body?
Kit lens AF is more then enough for people photography, even if they jump like crazy (happends on weddings too).
Start with EF-S 2.8 17-55 range zoom. Sigma, Tamron and Canon makes them. Check on Sigma 30 1.4 instead of Canon 50 1.4. If you going to try H&S portraits, 85mm prime is your focal length, not 135, it is way too long for indoor use on Rebel.
You not going to get any reasonable difference in IQ between overpriced, not available yet, non-IS Brick-II lens and EF-S IS analog for shooting office events without flash light.

My advice to the OP. Spend a great deal less time reading forums and grab a inexpensive EFs 18mm-135mm and spend more time shooting. Find the subject matter you really want to shoot and the focal length you shot most. Once you learn something about the craft you'll start learning about the art and maybe even more than one speed light will be part of your normal kit as well. There is no photography without light.

MrAl wrote in post #14587216
There is no photography without light.

^^^
Awesome!!

belias1989 wrote in post #14585588
I don't have any shooting style. I currently have a kit lens that comes with the 600D and I find it okay with office gatherings and occasions, further reach will be nice. I also don't want on changing lens often since and I also don't want speed lights so that I can comfortably attend on gatherings (e.g. weddings) comfortably. Fast focusing is a must but image quality should not be sacrificed. To make it short I want a top quality lens for general purpose.

The imboldened just described what you need.
In other words, you need the 24-70 f/2.8.
The MkII is out, and it's about $2300.
The original is still easily available for $1700.

belias1989 wrote in post #14586598
you got a point there, but I still have my 18-55 kit lens. 17-55 vs. 18-55 seems overlapping except for the quality of the glass. Kit lens still serve it's purpose.

you really think the 17-55 and 18-55 are in the same ballpark lens wise?...55mm f2.8 vs. 55mm f5.6 is a huge difference...