Many of you already know about it, but I thought I would mention it for those that don't. There is a notes.ini reference that is kind of nice. There are additional features as well, such IniGen, which is an ini generator and IniDiff, which will compare two ini files and display the differences. The ini generator will group the items in your ini file if you wish and give recommendations as well. Best of all it is free. You might get some e-mail (you can even have the generated ini file sent to your e-mail), but hey, you can signup with your Gmail account.
Words of caution. Before making changes to your .ini file, make a backup, test your changes, and for your sake document the changes (so you know what you did). I have not gotten into it to much as I am not the Notes Administrator, so I am not sure if all items listed are IBM/Lotus supported (yes, there are some undocumented ini file settings out there that aren't supported - some which come and go from release to release).
Thanks DRC Consulting for having it available. I have not used any of their other products, but since they are nice enough to host this reference free, I guess I could give them a plug and mention that they also have products (such as no.Spam.domino) available for purchase and you can replicate the ini reference database for a fee.
I must admit that I am still a bit paranoid about things like this and do dummy my server names and the like before submitting for it to generate the ini for me. Just note if you would do the same you have to change them back before trying to use it. They have been offering this for a long time though and I have not seen anything bad about them, which does raise my trust in them.