I really think I've reached my limit with my 2.5 year old.. she can be a really wonderful little girl, but it seems that as soon as we get through the front door she starts up. This generally involves doing exactly the opposite of what I ask, then running away. It all seems to escalate into a chase battle and me having to drag her to whatever it is I want or need her to do (usually going to bed or leaving the house).
An example:
Me: It's time for your bath now. Please come to the bathroom and brush your teeth.
DD: No, I want to watch TV.
Me: It's too late for that, it's time for your bath. Come with me to the bathroom and we'll brush your teeth.
DD: No! (runs off)
Me: I've asked you twice and I don't want to have to ask you again. I'm going to count to 3 and I need you to be in the bathroom before I get to 3.
DD: NO! No counting! (runs faster)
Me: Well, you need to come into the bathroom now.
(chase DD until caught, pick up and wordlessly deposit in bathroom, DD runs off again, repeat)
Once I eventually get her into the bathroom she'll lie down on the floor face-down so I can't pick her up; I try to brush her teeth and she'll wrestle the toothbrush out of my hands; I give a two-minute time-out and then the whole process repeats itself.
I'm trying the 'jar of pasta' approach but she's not quite got the concept yet; I've tried the 'if you don't do this by the time I get to 3 I will not read you a bedtime story' approach; I've tried moving bathtime to much earlier in case she's overtired, but nothing seems to be helping. DH isn't around much and hasn't been hugely helpful ('well, if she doesn't like it, then just don't bother' - all very well except when you have to leave the house). HV said I should make her do what I want to, even if it means pinning her down, and 'she'll soon learn, but you will go through a lot of screaming and hitting for a few months first' - which sounds a bit much.
Like I say, she can be a real delight but she seems to have cornered the market in selective hearing. I lost it the other day and said "You're a nice girl, not a spoiled little brat, so please act like the nice person I know you are," which resulted in her gleefully saying "I'm a spoiled little brat! I'm a spoiled little brat!" all evening. 
Is there any hope? She's also turned into a really fussy eater but I'm past caring about that - I'd just like to sort some of the defiance out first.
Sorry this is so long but I'm at my wit's end!