When looking for what can be uninstalled to reclaim space:
rpm -q -a --qf "%10{SIZE}\t%{NAME}\n" | sort -k1,1n
Sample output:
51721748 boost-devel
57180821 wireshark
65074768 libgcj
71492413 db4-devel
79152667 valgrind
85414200 java-1.6.0-openjdk
108920679 kernel
112425302 glibc-common
115976633 squeezeboxserver
116424867 kernel
116467238 kernel
204226588 fluid-soundfont-lite-patches