I strongly recommend installing cooked ROMs. They are optimized in every way imaginable, and come with some great freeware, too. They are FAR superior to any "official" firmware.
It's a little tricky to flash them, though. I can do it in about 5 minutes, but you should be careful since many things could go wrong, and you could end up with a brick (that you could revive yourself of course, but it's a bit of a pain).
Fortunately, XDA-Developers made a great guide:
http://forum.xda-developers.com/showthread.php?t=416211
The guide details the following:
A. Installing HardSPL to enable flashing cooked ROMs (kind of like jailbreaking an iPhone).
B. (optional) Flashing a "radio" ROM that marginally improves wireless reception and battery use.
C. Flashing the cooked ROM you prefer.
Here's a much easier and faster way to flash a cooked ROM that is not in the guide (you can do it only after installing HardSPL, though):
How to Flash Rom using Internal Storage Method , a safer, quicker and better way to flashing
* Rename *.NBH file to DIAMIMG.nbh (if it's not named that already)
* Copy to the root of Internal Storage (the 4GB internal flash memory drive)
* Soft Reset (red button under the stylus) while holding volume down button + back button <----
* Follow instructions on screen
Here's my favorite ROM. Credit to Duttythroy:
http://rapidshare.com/files/180717356/Duttys_5.2.20764.1.4.3_V4_Full_MSVC__2.03_.zip
Password:
Code:
V4 3.02 Produced by Dutty
Some great freeware:
G-Alarm: A wonderful alarm application.
TCPMP: A free media player that can do it all. Plays most desktop videos with no need for conversion.
Google Maps with Street View: As seen on the iPhone.
PockeTwit: A wonderful Twitter client with a great interface that can automatically upload photos and send your GPS location.
Skyfire: A free web browser that can play almost any video on the web.
Flash Player 7: Adds flash support to Opera Mobile and Pocket IE (not as good as Skyfire, though).
S2U2: Adds slide to unlock, a la the iPhone. Very nice, with many customization options.
S2V: A companion program for S2U2, mainly to choose another wallpaper.
Other freeware is found here:
http://freewareppc.com/
Install all to Internal Storage, except Skyfire and S2U2.