Graco Ultra Max 695 high boy. However I don't think you want to spend $2000 for a spray rig.
The questions to ask yourself,
First: How big is the house/area to be painted. Will it take me just as long to brush & roller it out as it would to set up a spray rig, spray it and clean the equip?
My 695 with 100' of line takes a minimum of 45-60minutes to properly break it down flush, clean, & relube it.
Also how many coats are you planning? Usually I will do one good primer coat and two top coats, making sure to back roller the final.
Second: What type of siding? Wood-v-stucco makes a big differnece. Wood prep is much more labor intensive than a power wash to stucco. Plus wood will require a little heavier primer than a repaint of exsisting stucco. i.e. prep is greater with wood....
Third: Because no matter the paint job the prep work is everything to it lasting the next 15-20yrs do I have (and want to spend) the time to do it right-v-finding a good painting contractor to do it?
These are a few questions you might consider. This I will say. You do get what you pay for in a painting job.
Don't forget you can rent spray rigs from Hertz, United & often the mom & pops too. No reason to buy a new unit for 500, if you can rent one for a weekend for 200.