If after yesterday's Feisty updates, your boot time is magically somewhere along the lines of a minute or two, it's because /etc/network/interfaces was overwritten, and it was overwritten with a lot of extra interfaces that you probably don't have and that it can't find on boot. To fix it:
sudo gedit /etc/network/interfaces
and change it to:
auto lo iface lo inet loopback #auto eth0 #iface eth0 inet dhcp #auto eth1 #iface eth1 inet dhcp #auto eth2 #iface eth2 inet dhcp #auto ath0 #iface ath0 inet dhcp #auto wlan0 #iface wlan0 inet dhcp
Alternatively, backspace out everything that's not lo. This won't break network-manager (this is actually how my /etc/network/interfaces always *had* to look for network-manager to work). It should fix your boot time though.
There is a bug filed for it. Someone did the update piece by piece to see what did it. He said ifupdown did it, but I rolled that back and the old version still has the problem. I think part of the installation of the new ifupdown was to rewrite that config file, and when that's the case, rolling back the package doesn't make any difference.