Thank you very much Gentlemen. Lots of input to work with now.
I'll have a look at every single one of your suggestions. Unfortunately some are out of my price range ($250+), but many of them would fit my budget.
I saw a Maxpedition Vulture II on Amazon for around $144, with free shipping to my stateside address. There is also a 5.11 3-day rush backpack in the same price range, but I don't know what the quality is. I have some 5.11 clothing and it's pretty decent.
Buying multiple cheap ones and just throw them away as they fade isn't something I really want to do.
The Camelback that TR suggested looks good too, plus it would give me the opportunity to hydrate while being on the motorcycle. I do have a Camelback, but it's the 3L hydration system only.
The Kifaru X-Ray would be the right size, but $376 is way out of my range.
LA Police gear has the kind of packs that I've used so far.
I have also found this:
http://www.amazon.com/Operators-Mili...ct_top?ie=UTF8
The price seems good, has the velco panel and small pouches that can be taken off or added if needed. Ever heard of VVV?
There is a Condor backpack as well that I haven't heard of (I have a rifle sling from them, didn't know they made packs):
http://www.amazon.com/Condor-Assault...=ATVPDKIKX0DER
Thank you again for taking the time and looking at this. I appreciate it.