Why would living so long possibly be boring? It would just mean that different kinds of things would be of more importance to you than normally would have been to a mortal. For example having a bit of 'luck' (chance), would you still care about it when you would live longer than the time that it will eventually mathematically MUST have happened once? Would you even still care about materialistic things? I doubt it. Would love be important? Depends..? Those are the kind of questions that I find interesting and being immortal would make you find out.

I think ideas will become more important than living a certain life, for example becomming a rockstar or president, but that would be in the long run, there are plenty of things to do in the first couple of millenia and since times change, there's a good chance you will never get bored. Actually aren't we still limited by past, present and future in what we would like to have been or be in a certain time? Being immortal doesn't mean you can live twice in 1998 and do anything you like within that time. Maybe after 1998 there will never be a world so full of nature as it is now, just to give a little example of what I mean. On the other hand positive changes could or since the time span is forever, would happen too.

Cheers