Who was it for you?
I.e., who was the first harmonica player you heard who set your feet marching on the blues harmonica highway?
I'll go first, tho' the time between that first hearing and when I finally took up harmonica (after playing a lot of other instruments) is measured in decades.
I grew up in a farming community with only one radio station. The station played every style. Pop, polka, classical, etc. My first memories are of artists such as Johnny Cash and Ricky Nelson. Then came Motown, the Brill Building (e.g., Bobby Vinton), and then the Beatles. Somewhere along the line I learned there was something called "blues," and had heard albums featuring Muddy Waters, Howling Wolf, et al.
Then in early 1966 my parents gave me as a gift the then-brand-new Vanguard 3-record set, Chicago/The Blues/Today! The first cut on the first side of the first record was Junior Wells' "Help Me" tribute to Rice Miller (Sonny Boy Williamson II). When the first notes came out of Wells' harmonica, I literally jumped out of my chair, wondering, "What the heck is THAT??" (I still do when I hear that recording.)
So for me, definitely Junior Wells.
Of course, "your milage may differ." For you, who was it?
I guess, for me, it's the tight but loose aspect of some musicians that appeals. Not necessarily one particular artist, style or instrument but the combination of atmosphere and musicality. Charlie Patton is an influence, as is Son House. Interestingly, Robert Johnson was reputedly a good harmonica player, maybe there's a subliminal bleed through in his lyrical delivery.