Nvidia’s new G100 chip might get the Geforce 9800 name. We know it's way too early for the final decision, but still, we got this from good sources that are supposed to know these things so much in advance.
It will be rather interesting in Q1 and Q2 as both ATI and Nvidia are supposed to launch two new high end parts each. In Q1 probably in January Nvidia is about to launch D8E, dual G92 card and ATI will reply with the already demonstrated R680 card. Later, probably in Q2, ATI will follow up with R700 to fight the G100.
We haven't seen any new high end cards since April, and that is way too long for this market.