Microsoft are making a concerted effort to improve user defined web based reporting by improving the functionality of Report Builder. The latest release is Report Builder 3 (RB3). Compared to the original Report Builder 1 there is almost no comparison as it has been made much simpler to the end user and does not involve clunky pre built models.
You will need SQL Server 2008 R2 to get RB3, otherwise you can play with RB2 in earlier releases. RB3 is essentially a subset of SSRS in Visual Studio, but delivered on a web page.
I delivered a 2-day course on RB3 recently. The trickiest aspect as always was getting the parameters working intuitively. The product is getting there, but not quite there yet.