I do 30 hours over 5 days, lots of my colleagues do 30 hours over 4 days, but I prefer shorter days so I can do the school run.
I work close to school, so with some longer days when DH is off duty and can drop off or pick up it works OK. I often have meetings over lunchtime and attend some evening meetings, which also helps with my hours.
Once I've left for the day I don't answer my blackberry, but I will answer the odd email if I'm waiting for something urgent.
I have an annualised hours contract which really helps. Im in a middle management role in the NHS, where part time and flexible hours is fairly normal, even in very senior posts.
I sometimes wish I had a day or two to myself, I work with several women who have school age DCs and work 3 or 4 days, but shorter days fits our family life best.
I'd second on-line shopping, I don't have a cleaner but I do flylady to keep on top of things, I have an ironing lady and I have a MIL who does the school run if I have an early/late meeting.
I'm planning to start a MSc in September, must be mad.