Do you want realistic simulation racing or arcade-style driving? Because the two are quite different, and different games will fill those two genres.
For realistic simulation racing, there really is only 2 good games that should be mentioned:
Both have their supporters and both have been designed to provide the most accurate and realistic racing simulation.
I tried iRacing, but ended up using rFactor as it was a single purchase and had a bunch of mod support (basically mods = free expansions for different racing formats).
As for hardware, a tri-monitor setup is definitely a great option for sim racing - and you can't go wrong with the G27 as a beginner. Although if you end up preferring F1 racing (and you have the budget), you might want to consider a wheel that is designed for F1 sim, like the Thrustmaster T500RS Ferrari F1 Wheel.
I guess the best thing about the T500RS wheel/pedals from Thrustmaster is that you can fit different wheels to the RS wheel base - so you could use a wheel for general racing, then switch to the F1 wheel for F1 racing when needed - but it comes at a price, it is very expensive.
As for arcade-style racing - I don't really care for it on PC, as that's what consoles are for