I've had good luck with the exfoliators, specifically the Equate brand from WalMart. It seems to be similar to the St. Ives which costs about 3 times as much. I buy the medicated kind which has salicylic acid in it in addition to the crushed up almond shells or sand or whatever they put in as an abrasive. For some reason the acid calms my scalp down a little after shaving.
I also have an after shave which I prepare myself which contains mainly Witch Hazel. I add aloe gel (the good stuff) until it just starts to thicken a bit and Tea Tree Oil just until I can smell it in the mix.
Between these 2 I don't have any problems with irritation.