First things first: “Summit” features the first appearance of Cliff Simon as a new recurring villain, Ba’al, and he is freaking fantastic. He is by far my favorite of this show’s many enemies. If they gave me the reins of Doctor Who tomorrow, I wouldn’t use the Master very much at all, but I’d offer the part to Cliff Simon. Ba’al is malevolent and smart and has a cunning that far outstrips the blunt-object idolatry of the System Lords, and Simon is completely amazing in the role. There’s another Goa’uld that I also like quite a lot, but we won’t meet him for quite some time, and he’s still no Ba’al.
“Summit” is a major episode in developing the System Lords. Three of the villains we’ve met before – Yu, Osiris, and Zipacna – are all reintroduced, and we meet five others, who are mostly one-offs*, and everybody’s getting together because somebody’s been wiping out their armies. So Vince Crestejo, who we haven’t seen in more than two years, is back, along with Anna-Louise Plowman and Kevin Durand. There are lots more speaking parts in this story than we normally see. Coordinating everybody’s schedule for this one must have been a joy.
Another reason I really enjoy this one and its follow-up: the heroes get themselves well and truly thrashed. While Daniel is infiltrating the System Lords’ summit with our old pal Jacob, Zipacna leads his armies against the Tok’ra. We saw the humans’ powerful allies the Tollan wiped out earlier this year, and now the Tok’ra are decimated. Even more surprising: just two episodes ago, we met Courtenay J. Stevens’ character of Lt. Elliot, newly assigned to SG-17. They all get killed as well. Elliot’s going to survive into part two, barely, but could this situation possibly get any worse? Tune in tomorrow night…
Fire Breathing Dimetrodon Time 
*The other System Lords: Svarog, Olokun, Kali, Bastet, and Morrigan. Sadly, a long and apparently very entertaining feud between Olokun and Yu is only mentioned in passing and left to our imaginations.