Here are some stats from my site... this is for the month of september, 
mostly today.

Should give you an idea of what the requests are, and how frequently you 
will see them.  

Code 404 Not Found Requests


        Total
        Requests             Bytes sent  | URL
--------------------------------------------------------------------------------------------------
     674  16.64%         185350   2.21%  | /default.ida
     283   6.99%          85466   1.02%  | /scripts/..%5c../winnt/system32/cmd.exe
     149   3.68%          41422   0.49%  | /MSADC/root.exe
     149   3.68%          41720   0.50%  | /scripts/root.exe
     148   3.65%          42624   0.51%  | /c/winnt/system32/cmd.exe
     147   3.63%          42336   0.51%  | /d/winnt/system32/cmd.exe
     143   3.53%          47905   0.57%  | /msadc/..%5c../..%5c../..%5c/..^^\../..^^\../..^^\../winnt/system32/cmd.exe
     142   3.51%          45298   0.54%  | /_mem_bin/..%5c../..%5c../..%5c../winnt/system32/cmd.exe
     142   3.51%          42742   0.51%  | /scripts/..^^\../winnt/system32/cmd.exe
     141   3.48%          42441   0.51%  | /scripts/..^