I wouldn't know how much of a bargain it is, I'm not very good with Newegg, although seeing other Phenom II X3 combos, it's about average. You do know that motherboard cannot unlock cores right? AMD removed the ACC feature on the SB850 chipset which that Gigabyte motherboard has.
If you don't mind not unlocking cores, then I suppose it is a good deal, but if you do want to, I suggest you get a combo which has a 790X/GX/FX NB and SB710/750.
Another question is, do you intend/need to use intergrated graphics, or a graphic card? If so, are you going to use two or more/buy one now add another one later?
If you don't need a graphics card, just get a motherboard with 785G or 790GX NB chipset (with SB710/750 if you want to unlock.) If you want to CrossFireX two + ATi cards (nVidia SLI isn't supported on AMD chipsets), then get a 790X/GX/FX with SB 710/750 etc.
Above is a good combo, a 770 + SB710 chipset, with USB 3.0 and SATA III too. This doesn't support CFX though, so this would be good if you're only going to use one graphic card.
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.353082
This is a good ASUS 790X motherboard can unlock cores, without USB 3.0/SATA III, but supports CFX 8x/8x.
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.349729
Want both SATA III/USB 3.0 AND CrossFireX? This combo is probably what you're looking for:
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.353109
Seems like the board has several SATA III problems. Then again, they're just Newegg reviews...
If you're not going to use any graphic card but want USB 3.0/SATA III - just get either a 785G or 790GX motherboard. Don't care about unlocking cores and you don't need a graphic card? Get this:
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.357877
SATA III and USB 3.0 as well, also has intergrated ATi Radeon HD 4290 graphics.