I tried writing something with "I" sometime, but I soon found myself thinking about it every time I wrote it and after a while, I started automatically going back to "we" and correcting it all the time.
For some reason, I find that "we" just sounds ... I don't know, better?
By the way, "we" doesn't have to refer to "we, authors"; it can also refer to "we, me (the author) and you (the reader)". Perhaps that's why I like it more. I just browsed through one of my favorite authors (as for writing style, at least), and I noted he often says we in derivations ("If we compare this to (...), we see that"). At other points he uses "I" or "you", e.g. "I'd like to show you now what happens [...]" or "Suppose you want to [...]".
Basically, what I think I'm trying to say is: go with your preference and just do it as it seems the most natural to you while writing (though checking it afterwards for consistency is not a bad idea, if you want to avoid phrases like "(I/We) have seen (we/I) cannot solve this").