I've just started using OnTime thanks to recommendations on this thread. And I gota say it's really quite good! Free for 2x users too so that doesn't hurt either
AtTask is what I am using. It provides project portfolio management, document management and resource management all together. Very efficient and saves time as its having web-based task management.
Has anyone tried their hand at using Agile Project Manager for iPad. Could be useful for those on the road or in bed
I would say Basecamp would be better if you are looking for a project management software that is very simple and easy to use. It is user-friendly and doesn't take a lot of time for you to learn how to use it. Projects are loaded in a single dashboard so you can easily see all of your projects. The calendar view helps you see your schedules, events and most importantly the deadline of tasks and projects. If you are looking for a project management software that focuses more on tasks, Zoho Projects would be better. Its features in tracking tasks and time is great for both staff and project managers. You can check this article for more alternatives. The article mentions various project management software with features and pricing listed on a table so you can compare them with each other.
As a freelance developer I'm using Microsoft's project management software. It helps me to be in sync with current/pending/expected project tasks. Its quite affordable given that I work on hi-end projects. And as you ask, it is highly scalable too, since it can be run over a connected platform.
We use project tracking software, which helps us manage projects and tracks it even. Its worth a try.