There seems to be many options. Many people recommend Basecamp. I've tried it, but it is not the tool we need. I'm sure it's great, but not for us. It's more like a communication tool. It doesn't build Gantt charts. Please advise what other tools are worth looking at.

Come on! MS Project is not Web-based! And it's one of the worst project management applications I've ever used. You might want to take a look at Wrike.com. We started to use it about 4 months ago and it's doing a great job so far. Our team is placed in 4 different cities and it's very handy for all of us to keep all the project relevant stuff in one place on the web. Wrike has timelines that stand for Gantt charts. The coolest thing about these timelines is that you can drag-n-drop tasks and dates right on the timeline.