If you want to experiment with loads: single stage / turret press. Redding T7 / Hornady Lock N' Load / RCBS Rockchucker.
If you want volume production of known loads: progressive. I'd go with a Dillon 550 to begin with, as it is easily upgraded to increase production.
If you're committed to reloading, the correct answer is both. A single stage/turret press for developing loads and small-scale production, and a progressive press for producing vetted loads in quantity. Eventually you'd want two progressive presses, one set up for large primers and one set up for small, as changing the priming system is a time-intensive task.
My personal set up is a Dillon Square-Deal B in 45 ACP, a Dillon 550 set up for small primers for loading .38spl and .223, and a Redding T7 for everything else.
One thing to think about if you go with a progressive press is quality control: taking time to spot-check and correct for any drift in the die and powder settings can save you a lot of time and frustration down the line.