My current favourite is a Suzuki Olive in E
The "C" is a good choice because 2nd position (the left end ) is "G" best for blues IMO. Playing off the main key helps to give more emotion to the sound compared to the natural note which will be cleaner. That raspy bluesy tone
To just play yourself the key does not matter a lot it is much more important if playing with other musicians so ultimately several harmonicas are needed.
It also helps to try a few to find what suits you. I have several Hohners (marine band and special 20) and don't like them as much.
I seen this gold suzuki real cheap so grabbed it. It was $200 + in Aus shops. (it is 9c gold plated). Got it for $60 AUD in Japan a number of years ago.
Also have a few collectors:
Made a mistake with the Bob Dylan as I could have bought the set for about 1K but only got the one individual. I later seen the set on ebay for $20K.
It can be a lot of fun.
christelle berthon is pretty good.