Here we go, I'll try to make this simple, though please keep in mind this is what has worked for me, it may not work for you. (some want different functionality, so please find what works best for you, I'm not trying to tell you what's best. ). Much of this information can be found in nearby threads, but I'll try to be succinct. If I've been unclear on something, please let me know. I'll address the points by number (though they aren't present on the original post), if you need any others explained, just ask me and I'll update this.

2. Unwanted Today apps: Most people are familiar with this, but just incase, goto Settings, Today, and Items. I'd remove any LiveSearch functions, and Sprint-based software plugins, as these just take up memory and are accessible by other means. Infact, I don't let any of my non-standard (i.e. not Messaging, Tasks, etc.) apps run in "Today" because they're just as easy to start.

4. IE Cache. Within IE, goto Tools, Options, and under Memory, click "Delete Files." Many of you are aware of this, (I'm not trying to patronize anyone here, please understand) so this is just for those who aren't familiar.

5. WMA ringtones work well. The best is to encode them in say, 48kbit/s mono. This is equivalent in quality (but not in spatial depth) to 96kbit/s in stereo, which is far more than enough to satisfy the needs of a ringtone. I'm a fan of higher bitrates, but keeping them small helps. Use an audio normalizer in your sound editor to normalize the volume to 100% so that you can take full advantage of the speaker's volume during your ringtone. Store all ringtones in \Windows\Rings

6. Get TCPMP (Google it, and download/install version 0.72 RC1 - newer versions exist, but 0.72 works just fine.) Then, get the AAC playback codec, available here: RareWares
be sure to select the WM version of the "Betaplayer" codec. Install the cab and you're in business for AAC-based content.
Under Options, Settings, Advanced, change the "Manual A/V Offset +/-" to -400 msec or so. This should help with the audio being out of sync.

7. Messaging: under Options, Storage, select "When available, use this storage card to store attachments."

8. Pair your BT GPS as usual. Then, goto COM Ports, and select a new outgoing port. Select your GPS device (hopefully, when you paired it, you selected "Serial Port" functionality), and select say, COM 2. Then goto "External GPS" in the control panel, select your GPS port (COM 2 if you followed above) under "Hardware" and then pick another port, say COM 4 under "Software".

11. Exchange - set this up in ActiveSync, though it'll require you to have access to an MS Exchange server.

12. In ActiveSync, goto Menu, Schedule. Change the values to whatever is most convenient to you. I have mine all set to manual, since I prefer to do those operations at my own discretion. This saves battery life. The same should be done for your non-Exchange e-mail accounts.

15. Sign up for the MS Deepfish trial. You might want to google it.

17. There is a thread in the forum called "GMail Java app..." that I created, and someone was kind enough to post a reply suggesting a JVM that does work well with GMail. Install this and use it to run the GMail app. I myself use POP3 to access GMail, so I don't have to worry about this.

18. This is a messy subject, and may still need some fixing in the form of ROM updates. All I can suggest is that if your callers are having trouble hearing you, speak up and you might not have issues with sounding like you're cutting out. This is, however, extremely variable.

Hopefully this post answers some questions that you may have had, let me know if you have others. For those of you that found this post obvious, I hope I didn't waste your time too much.