I recommend you check out Oncomine (registration required, somewhat limited free version available for academics). They have genome-wide expression data for thousands of cancer samples and have recently added 917 cell lines from the Cancer Cell Line Encyclopedia (CCLE) and 732 cell lines from Sanger's Genomics of Drug Sensitivity in Cancer project. Both performed array-based expression profiling (among other technologies) of a large number of cell lines and assayed those same lines against a number of cancer drugs. Oncomine has a user-friendly interface (once you get used to it) for exploring gene expression and differential expression data in cancer. If you want raw CEL files, the CCLE data (U133Plus2) are available through their site and the Sanger data (U133Av2) were deposited in ArrayExpress (accession number is E-MTAB-783). They also both provide interfaces for exploring their data which may be helpful depending what you are trying to do (its not clear from your question).
I'm not sure if you will be able to find both gene and miRNA expression data together very easily though. Most platforms measure one well and not the other.