Discipline help with 4.5yr old

So my son has recently started getting really snappy with rude comments, not listening, not wanting to do certain things (baths, bedtime, brushing his teeth, getting dressed..), back talking. I'm fairly certain it has a lot to do with some of the kids at daycare (in the afternoon it's a mix of 4-10yr olds) Anyways, we've cut out TV watching period. Some of the shows he likes probably influenced some of it too. He can watch Mickey mouse with his sister and that's about it. Time outs are not working anymore. Talking to him seems to go in one ear and out the other. Taking toys away doesn't phase him. I'm running out of ideas. My DH and I try very hard to get down to eye level and explain things to him without yelling. Sometimes voices get stern though whatever the situation is. He's a great kid and usually does well, it's just lately his behavior has been challenging.
We started a sticker chart and at the end of the week he gets to pick a movie for the night or a snack at the store. He's pretty stubborn in the listening department. I need some more ideas to work with? We do not spank, so that is out of the question.

TIA

do u do a small reward at end of the day?
my son acts out for attention, but Dean has odd and adhd, he is basically a defiant teenager in a 6 year old body, his Dr. said for us to praise good behavior and kind of ignore when hes misbehaving, so he flips how he seeks the attention

Quoting DeanJade&Maksims Momma:" do u do a small reward at end of the day? my son acts out for attention, but Dean has odd and adhd, he ... [snip!] ... his Dr. said for us to praise good behavior and kind of ignore when hes misbehaving, so he flips how he seeks the attention"

We do not, I'd like him to work up to a reward and realize on days that are not so good days how he can change that and control behavior. Daily rewards have not worked in the past for him.

Quoting K[♥ E&C]:" We do not, I'd like him to work up to a reward and realize on days that are not so good days how he can change that and control behavior. Daily rewards have not worked in the past for him."

ohhh, that sucks we let Dean add 3 songs to his playlist on tablet, we also use an app on his tablet, dean logs his own behavior, maybe 4 times a day

http://www.appszoom.com/android_applications/education/behavior-status_qkpt.html
this is what he uses