Well, as True found out himself, I've improved my Cammy play a bit.

Not giving up on her, I enjoy playing as her way too much! While it can be frustrating playing at times, playing as Cammy, winning with her feels great.
Thanks to playing against an old friend of mine (an old hand at SF2 and excellent Guile player), I learned to mix up her moves and inject the occasional "shock and awe" to really throw off opponents. For example, an opponent jumps back thinking they're safe, only to find their face being driven into the pavement by Cammy's EX Hooligan Combo.

Also, it's very important to try and avoid doing any obvious special moves - such as using a plain Spiral Arrow which is easily blocked/countered - and to try and weave more normal attacks into her play style. After all, Spiral Arrows and Cannon Strikes are excellent as part of a combo (started by a normal move). EX Spiral Arrows also work better than Spinning Backfists as a fireball counter.
In short, don't try to save the EX meter for Cammy's Super. Just burn it whenever the opportunity arises. After all, Cammy is an all-out offensive machine when there's an opening - and she is fast enough to exploit the smallest openings. NWM is very right - you need to be patient to play as Cammy, then blitz your opponent when you see an opening! She really plays best as a bait-and-punish.
I gave some other characters a try, but I haven't decided on my secondary yet. I doubt it'll be Chun-Li as I feel I don't suit charge characters.

;; I'll definitely keep looking, as playing as other characters does really open up new angles to you.
My win rate has gone up a lot, and I'm getting closer to beating my friend's Guile! His Guile is very tough to beat, but I think I'm starting to get some of his patterns down and see ways to bait/punish him.
Awesome, Daniee! Hope to see you back online soon.