The problem with the HTC Incredible isn't one app or another. It is part of the original design of the phone storage software. You can temporarily solve the memory error problem by locating an app and deleting it, but you have suppressed a symptom, not the underlying cause.
The problem can be explained better with a little back history. The Incredible has 3 memory locations: the memory card (which you can access and alter on your pc), the memory where the new apps are installed (which you can access and alter on your pc), and the data memory (which you can NOT access nor view in any format, any place, any way you try on your original phone or computer). These are not the official names for the memory locations, but I've gotten so many different names from customer service that I'm calling them by their best descriptions instead.
This data memory location is not very big, and fills up easily. When it fills, regardless of how vacuous and empty the memory files are that you can actually see (card and app memories), you get the dreaded error message and the resulting dysfunction of the phone's functions. It holds 1) the system files, which they hide from you for good reason, so you don't crash your phone's operating system just diddling around by accident. 2) your texts, and I'm not sure why we aren't allowed access to our text files. Maybe a legal thing? And 3) app data files. Which apps? We don't know. Which data? We don't know. We don't know because we can't see inside that memory location. Some apps deposit their data files in this memory location, and other deposit them in the app's program folders where we can see them. There doesn't seem to be any restriction on where they get to store their data. Not all phone makes/models have this bug; many others don't allow anything new to be downloaded into their small data memory location.
Obviously some of the apps who deposit their data in the tiny memory location have been discovered by this forum (Mail, Facebook, Google Earth, etc.) By deleting the app, we make some space in that tiny folder and our phone works again for a while (maybe even forever!). So we think that the app was the culprit. But then for many of us, it happens again and we delete yet another app. I am to a point now where I have zero apps that do not come stock on my phone, and I delete all but 10% of my texts (the most essential ones). All stats I can see say that my phone is nearly empty. Yet the error message still tells me my phone is full. All I can do is try to keep my texts deleting right after I send them, because you can't access them again to delete one if the memory fills. Basically, if I forget, I can't fix it within the texting app because I'm locked out. So I have to delete another app in order to get back into the text app to delete more texts. But I don't have any more apps to delete. I only have the original apps which I'm not allowed to delete. Fairly soon, I won't have any more texts to delete either and my phone will cease to function for anything besides calls (and that has stopped once also, when I didn't find a way to delete something more).
I think my phone is a special case--one who takes this problem to a whole new level of sensitivity in the memory space. A lemon, if you will. I have heard that my only real option is to root my phone so I can finally have access to that elusive data memory location and clean it out well. I'm not a techie and I've never done it before, and there's a risk of accidentally bricking my phone. But, my phone is slowly but surely turning into a brick anyway (if I can't use it for apps, texts, or calling...). It is in my near future. Shall I return and report if I do this?