There are a number of really great solutions out there for Enterprise Reporting. Within the big four (BO/Crystal, MS SRSS, Cognos, Oracle) the basic reporting functions are all covered. You really need to evaluate what core functionality is most important to you and what the pre-dominant architecture in your environment is.
The consolidation within the BI market has made the environment issue all the more relevant. If you have an Oracle enterprise, you may as well use Oracle BI. The same applies for SAP/BO, IBM/Cognos, and Microsoft. Particularly if you are making a new BI decision.
Finally, there are a number of Open Source solutions (BIRT, Jasper, Pentaho) that make sense if you are an OSS shop or if you are looking to avoid some of the licensing fees associated with the major BI players.