Dear Satya -
Both are very much important in day to day Data warehousing methodology.
Just for example, if you are asked to choose the best from both of your eyes.... Which one you choose..?
In the same way, the ETL and reporting tools are dependent on each other.
But if you want to choose the best in the market, go for Reporting side, if you have enough knowledge on back end systems (databases, etc)
hope it answers your question, get back to me; if you need any furhter info..