50mm [...] is comparible to using a 75mm lens on a Full Frame Sensor camera [...]
Exactly. 75mm FX equivalent.
[...] You're not going to actually be shooting at 18-55 [...]
Nope, you are shooting at 18-55mm - just the field of view is like the one from an 27-82.5mm lens on FX.
That's why it's called equivalent.
When the Nikon D1 came out in 1999 the 1.5x crop factor was for 35mm film shooters to understand what they had to cope with when shooting digital, since a 28mm was no longer the wide angle it used to be etc.
Now it has become some sort of mystery. Even people who bought their first SLR immediately learn that their lenses do not have the focal length(s) which Nikon labeled them for -- "because of the 1.5x crop factor of the DX body".
It might seem like nitpicking, but I think one has to be careful here. First time DSLR buyers can easily get confused and then we are confronted with questions like "Is my 35mm DX lens 23.3mm on an FX body?" or "Does my DX lens not change its focal length by 1.5 when mounted on a DX body?".
Somebody who never shot with the 35mm lens mounted on a full frame body does not know about those differences and should therefore not be confused -- especially by sentences like "Your lens is not 35mm". It can easily lead to total puzzlement and I have seen it happen more than twice. That's my opinion. Pasta.