I've had sky broadband for over a year now, and have used this site loads for useful information. I've now joined up so that I can share this tale....
...Basically we've always had a very intermittent connection. Connection speeds were about 4.5 mbps, which is about right considering our distance from the exchange. Over a period of time, it became apparent that the connection problem was most often when the weather was bad (eg rain/wind). We lived with this as we're not exactly huge broadband users, and couldn't do with the hassle of contacting technical support as we both work and didn't fancy being on hold - especially when sky BB was in its infancy.
In the early summer, my wife went onto maternity leave and was therefore using the computer much more (she obviously had nothing better to do!). As I'm sure you remember, the summer was not remembered for too many long spells of sunshine (having said that, I write this as a thunderstorm rumbles outside!), so she ended up phoning technical support - the account is in her name anyway.
We went through the tried and tested connection questions. As it happens, there is an alarming amount of wiring from the master socket to where the router is, but I can assure you that there is little advantage in plugging directly into the master socket (or the engineering socket for that matter). After several chats with the tier 3 people, we got BT onto the case. Within a few days, an engineer was round. According to them, it was a crossed line at fault. Unfortunately I've no idea what they did, but they have done something with the 2nd (unused) line that comes into the house. Since this visit, our connection speed has dropped, and we can now not get a speed greater than ~1.7 mbps. It also drops every now and then, although it isn't as bad as before. I spent about 30 mins on the phone with a sky engineer as he tried to tinker with the connection speed, but to no avail. BT were dispatched again, and this time changed the wiring from the pole outside to the house and the socket with the screw in the middle (can't remember its name). Whilst he was here, he hooked up a BT modem on his laptop, and could get no more than 2 mbps. Sky are adament that we are not capped. BT have done other things at the exchange, but this too has made no difference. Sky have now sent us a new router (even though I told them that BT couldn't get > 2 mbps!), but surprise surprise, this is not showing any improvement. I am certain that whatever the first BT engineer did has caused this drop in speed, but trying to get that through to the folks at Sky technical support is proving difficult. They are now refusing to connect us to an engineer unless we have the new router plugged into the master socket for 48 hours! Would they know if it wasn't?
Anyway, I am reluctant to do this as we don't use wireless and I'm sure it won't make any difference - it hasn't done on any previous occasion. They also keep closing our case thinking that everything is OK - do these people not keep records???!!!
I'm now pretty annoyed by the whole thing and not really sure what to do to get the message accross - hence this long and drawn out post (apologies for that!).
I'd be grateful for any assistance or advice that anyone out there could offer. I know we're going to have to speak to them again, but it would be nice to be armed with some info that anyone can offer .
Here are my frankly embarrassing stats :

Router Statistics
System Up Time: 0:59:48

Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN PPPoA 8315 9251 0 279 3052 0:58:58
LAN 12352 10945 0 3136 375 0:59:48
WLAN 355 0 0 0 0 0:59:26
ADSL Link Downstream Upstream
Connection Speed 1664 kbps 384 kbps
Line Attenuation 50.0 db 27.0 db
Noise Margin 7.0 db 14.0 db

All these numbers have remained pretty unchanged over this whole saga, except obviosuly for the connection speed!