This is a very good article explaining the current Business Intelligence Magic Quadrant Platforms:
Magic Quadrant for Business Intelligence Platforms
I've used Business Objects / Crystal Reports, Microsoft SQL-Server Reporting Services, OBIEE, Actuate and I prefer SSRS myself.
As far as the up and comers, I've tested QlikView & Tableau.
If I were developing reports, because I've been in the Reporting industry for 16+ years, I might prefer QuikView because it's very powerful and has great depth of customizable features.
However, if I were pushing the software upstream to the Exec's & Power Users who have limited or no formal SQL training, I would prefer Tableau, based on my initial evaluations.
Granted, I have not spent an enormous amount of time with both products.
That's my take on it, for what it's worth.