Red - I can't help you with mums but as a region it really isn't that bad. Bits of it are Stepford-esque, but you can avoid them! Sorry for the long post, but I had a really, really good time in my 2.5 years in Virginia and I've become bizarrely fixated with other people enjoying it too!
The tick problem is to do with (a) white-tailed deer and (b) Lyme Disease. Hunting is not allowed in most Virginia towns (outside the towns, of course, it's positively encouraged!) so you get a lot of urban deer, which harbour ticks. If you play anywhere a deer might walk (including some of the large Reston back gardens) it's worth looking out for ticks and removing them. Lyme disease is rare and difficult to catch - the longer the tick is attached, the more likely it is to transfer - hence the checking! I hiked regularly in the National Park in Shenandoah and never picked up a tick, so it's not a foregone conclusion, but I was on my guard. If you get a tick bite and then a ring-shaped rash, especially accompanied by any illness, see a doc for antibiotics.
Thinking about your comments (and everyone else's) it might be worth thinking about living slightly closer to DC. Your DH would be commuting against the traffic. Northern Virginia traffic is notorious, but it's only REALLY bad if you join the rest of the region heading into DC in the morning. My DH commuted from Ballston in Arlington to Fairfax - took him 10 minutes in the car. And NOT living in Fairfax was the best decision we made when we moved. To be fair, a commute from Arlington to Reston would be slower, and would involve the toll road (Dulles Access Road). Timing would also depend what time he set off in the morning. My DH left the house by 7.30am most days. Anyway - I think a 'good' time from Ballston to Reston would be 20 minutes. If your DH is willing to drive a few miles every day, you might find a more recognisable way of life closer to DC. You could think about Falls Church too - it's got a high street and a metro stop. And Vienna has a metro stop (but is otherwise pretty dull).
Re: finding friends who take the piss out of one another... It's slightly difficult because there isn't a good American term for 'taking the piss'! But the requisite sense of humour DOES still exist. By the end, I was thinking of this as the David Sedaris test. People who listen to WAMU (local public radio station - roughly equivalent to Radio 4) and like David Sedaris will also understand irony etc. It took me a little while to settle into my new friendships, but people were friendly enough that I was happy to take the time. NMC is right about making appointments, but you can do that with your cellphone (so get one of those, pay-as-you-go if necessary, when you arrive) in a relatively informal fashion. My DH's colleagues and their families (even the yummy mummies) were INCREDIBLY welcoming and kind and loved the idea of teaching the newbie how things work. So I let them!
What else... Harry Potter! Alexandria (another town in Virginia, walking friendly as NMC mentioned, but probably an inconvenient commute for your DH) had a Harry Potter night when the last book came out. The kids were all out on the street in fancy dress, the book shops opened til midnight, some of the restaurants served special Potter menus all night, and there were ghost tours etc etc. As a home-schooler, NMC will have met the maddest of the mad, the most evangelical of the fundamentalists, the craziest churchgoers in the area. Often in the States, home schoolers choose that option to stop their kids learning about evolution, godless heathens, magic, ghosts etc. Luckily for the rest of us, that means they're nicely out of the way! Very problematic for pink-haired hippy British home-schoolers, though, I would have thought! Poor NMC - I can't even imagine it - you were possibly the bravest expat in the world! I didn't talk about religion until I had known someone a few months, and I NEVER talked about abortion. But I didn't have any of the problems I expected to have as a leftie atheist. And, to be fair, I don't talk about religion here, either - it just used to make me more nervous over there.
And finally... Washington, DC. NMC is right - you can see poverty on the streets. I can see poverty on the streets right here, though, and I live in a beautiful cathedral city in the south of England. I worked in DC for most of the time I lived in Virginia. In fact, I worked two blocks from the White House. It's safe - it's full of tourists and office-workers. Don't be put off coming into town to enjoy the museums (and I liked the zoo, too - don't tell NMC ). Hundreds of thousands of small-town Americans fly into town every year and nothing bad happens to them, even though they wouldn't know a junkie if one bit them in the ass (sorry, arse). DC is an odd place - small enough to walk around, but rather institutional - big, beautiful marble buildings, but sometimes half a mile between coffee shops! Most of the poverty and street crime is confined to South East DC - don't cross the Anacostia River and you'll never see it. If you've ever lived in London, DC will feel perfectly safe as long as you stay broadly in the centre. There's so much (great, free) stuff to do in the centre that you're unlikely to want to go anywhere else, though!
Sorry for going on and on. It's really a beautiful, fascinating part of the world. Just stay away from the Stepford Wives!