Hell no. Not for a long, long time at the very least. HTML5 is still in early days and it doesn't have great stability with all browsers at the moment, as well as mobile devices, etc. Flash still has more to offer than HTML5 does and there are too many Flash-oriented websites which aren't likely to change, i.e. Newgrounds, which predominantly hosts Flash games and movies.
HTML5 will replace a lot of currently-Flash based websites such as YouTube, but it's unlikely it will completely replace Flash.