Is the marketplace crowded?

[eluser]Milos Dakic[/eluser]
Just wanted to see what the community had to say about the current market for web applications. I have been looking into developing a few web applications for things like project management, invoicing, documentation etc. What do you think of apps that are already available? What don't you like about them? What would make you want to move to a new app of that sort?

I will potentially base my ideas of currently existing apps but would put in my own touch and features as that is why I wanted to do something like this in the first place.

Hope to get some feedback from people who use such apps and to see what they think.