If you want to model heavy duty mainline railroading in 2-rail with big steam and long freight and passenger cars then by all means go for it...and by all means take some pictures of your giant layout with 72" radius curves and large turnouts. I truly enjoy seeing those layouts, and I envy those of you who have the space.
If you want to model heavy duty mainline railroading in 3-rail with big steam and long freight and passenger cars then by all means go for it...and please take lots of pictures of your (not necessarily) large layout and all of your turnouts (you can fit more of them into your space).
i truly enjoy seeing those beautiful 3-rail layouts, and there are more of them out there, because more of you have room to achieve your goals.
Just be aware of two things--
The third rail just eats away at some people, and they will do their best to make you feel inadequate. This probably won't bother you that much, because you will still have a beautiful 3-rail layout, and it will actually fit in your basement.
The second thing is much more serious--by building that 3-rail layout you are giving up the chance to marry Shallow Hal's daughter. Somehow you must learn to carry on in spite of that...
Jeff C