Depends on your commute, I run a 1x9 with 11-28 cassette on 26" wheels using a 46T front wheel, with that I average 18mph over my commute and can still grind up the steepest hills I have to climb.
Really almost anything will do but you'd be best off adapting a double chain set for the best chain line. You'll need a chain retention device as well, either an old front mech, a proper chainkeeper (superstar components do a decent one) or some chain guards. I have a SRAM apex chainset with a 38t ring, an outer chainguard and a dog fang to keep the chain from coming off the inside and have used this from cx racing so I know it's pretty secure.
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retired 9.6kg Carrera Kraken
The Carrera Hardtail combined thread - come on all you Carrera's!
The Sons Scott Genius RC20 build