Ever since either the last update, or the one before, it seems the phone has really bogged down.
I haven't really done anything fancy to it. I don't really use very many intensive apps, either. Other than the occasional text/e-mail/phone call, that's about it.
It seems to drop a wi-fi connection in favor of 3G sometimes; it will also have difficulty getting back on a network it's been on for almost two years now.
In addition to the above, it just seems to have slowed down tremendously.