Version 0.3.10 patches the block 74638 overflow bug. http://bitcointalk.org/index.php?topic=823
The Linux version includes tcatm's 4-way SSE2 SHA-256 that makes generating faster on i5, i7 (with hyperthreading) and AMD CPU's. Try the "-4way" switch to enable it and check if it's faster for you.
Download from sourceforge:
http://sourceforge.net/projects/bitcoin/files/Bitcoin/bitcoin-0.3.10/
SHA1 16645ec5fcdb35bc54bc7195309a1a81105242bb bitcoin-0.3.10-win32-setup.exe
SHA1 4f35ad7711a38fe8c880c6c9beab430824c426d3 bitcoin-0.3.10-win32.zip
SHA1 e3fda1ddb31b0d5c35156cacd80dee6ea6ae6423 bitcoin-0.3.10-linux.tar.gz
SHA1 b812ccff4881778b9090f7c0b0255bcba7b078ac bitcoin-0.3.10-macosx.zip
It is no longer necessary to delete blk*.dat. The good block chain has overtaken the bad block chain, so you can just upgrade and it'll automatically reorg away the bad block chain.