[colonel]

All web requests directed via RIM will go slower then direct to the internet

So having an APN customised for your provider will always be faster

[jimfraser]

Originally Posted by knottyrope

you can always enable it later on. i dont have any issues with any of my apps at the moment.

For Flycast and Nobex Radio I needed APN for them to work on my 9000 when receiving them over the mobile network. When using these programs I am usually on WiFi (in fact Nobex warns you about data use if connecting on mobile network) so APN is not an issue then.
My APN settings were ported over when I switched to 9800 and both Flycast and Nobex work fine over air (and wifi). As APN settings are network specific I think that I will continue to need my APN settings for Flycast and Nobex to work over air with my new hardware and software. I will check this out at some point.
Never tried youtube without APN settings, but suspect it would not work because its data bandwith requirements (as well as the streaming radio programs noted above.) Can't imangine what RIM's server and/or our BES would do with all this data stream.