Originally Posted by Rockman
Sketch the garage first and build the house around it!
THIS!!! Seriously, if you are a gear head, this is a big consideration. Wife wouldn't put up with a substandard kitchen, so neither should you.
Think big closets and storage space if that fits into the picture.
Regarding stairs, I made a similar mistake (well the architect did and I didn't catch it until it was too late. Had to make an additional landing and turn on both sets of stairs because not enough room was allowed at the bottom for a landing. Figure 12" ea for treads (run) and 7" rise. 17' of run allows you 17 steps which will get you up/down about 10' vertically. If you have 8' basement walls you'll be at 9' total rise to get to the main level floor from the basement floor.