The 21.5" 2.7GHz current generation iMac is seeing a $149 discount at Adorama and Best Buy. The iMac, however, is near the end of its refresh cycle and while we probably won't see the new low-cost iMac debuted at WWDC, it does seem imminent. So, we recommend you wait on buying any new iMacs.
The 13" Retina MacBook Pro with 512GB SSD, however, is seeing a $199 discount at both Amazon and B&H Photo, bringing the price from $1799 to $1599.99. That's the lowest price we've seen. The buy recommendation for the Retina MacBook Pro is more complicated.
The Retina MacBook Pros were last updated in October 2013, according to our Buyer's Guide and receives a "Caution" rating. Current MacBook Pro rumors place the next update in between Q3 and Q4, so approximately 4 months from now. That is enough time that if you are on the market specifically for the 13" Retina MacBook Pro, a $199 discount may be enough to pull the trigger.
B&H Photo and Adorama only charge sales tax in NY and NY/NJ, respectively.
MacRumors is an affiliate partner with some of these vendors.