If you have a DirecTv account yourself, you can get a $100 referral bonus, but you have to go through a special phone number with DirecTv and there are pretty specific steps you need to follow. Information on that can be found on D*s web site.
Aside from that, I don't know if there are possibly new subscriber deals that you could get through DirecTv that you may not be able to match with a retailer or not or if it will all be the same. For that matter, you could also go through some on-line retailers and get some deals as well.
The thing to be aware of if you're not already (from your join date of July 2006 I'm guessing you're aware of this) is that pretty much all equipment they would get now is leased and comes with either a one year (for the basic Standard Definition receiver) or two year (for pretty much anything else - HD or DVR) programming commitment.
If you're not familiar with that, read up on that and make sure they're OK with it.