SUN Microsystems announced end of life (EOL) for V125, V215, V245 and V445. For SUN Fire servers powered by UltraSPARC IIIi last shipment is July 11, 2008. After this date only SUN Netra servers with UltraSPARC IIIi processors will be available.
If you are interested in the SPARC family follow this link to wikipedia.
SUN provides several upgrade paths:
Move to UltraSPARC T1 or T2 if single thread performance is not critical (e.g.:Sun Fire T1000 Server, Sun Fire T2000 Server)
Move to SPARC IV+/IV single thread performance is critical and you have to stay on SPARC architecture (e.g.: Sun Fire V490 Server, Sun Fire E2900 Server)
Move to AMD Opterion if single thread performance is critical and you only have to stay on Solaris (e.g.: Sun Fire X4200 Server, Sun Fire X4200 Server)