I'm not mad about flash cards either really, but know so little about phonics and teaching phonics, that I thought it best to go with the scheme he'll be using at school - I didn't want to teach him in a way that needs to be corrected once he starts at school!
We have not used any RWI books though - sticking with a few phonics books from the library, and one he got from a book start pack, which was a comics for phonics book (I'm hoping school has more of that range, as he loves it!). It's all about balance though, isn't it? Like he wants to know more about numbers, and I am no mathematician, so we are just counting house numbers when walking anywhere - going 'ok, that's 2, what is 2 more? yes! it's number 4! what's 2 more than 4?' and so on. So he thinks we are just playing a game, but he is inadvertently learning :o
We are doing similar with letters, and he reads EVERY road sign and house name we come across, and was trying to read some registration plates the other day, and wondering why they have numbers in them. I think he will enjoy RWI at school though, as they will obviously spend more time on it than we do at home. I am doing my level best to make home life as dull as possible at the moment, and getting him and DD to play together doing more imaginary play. This is not entirely altruistic, as I'm hoping they'll give me 5 minutes peace sometimes, but we'll pretend it's totally for their own benefit...