If you really want a stable production environment I would go for either RedHat Advanced Server 2.1 (RHAS) or SuSE Enterprise Server 7 (SLES7), depending on what application to use. For SAP/R3 i would go for SLES7 and for other uses I would go for RHAS.
I know that you have to pay, but advantage is that support will stay until 2005.
If you don't want to pay go for RH7.3, but know that Errata support will end december 2003.
Regards
Kjetil