If the
gross factor is all that's keeping you from watching, I will list episodes where you might want to fast forward over a gross scene. How does that sound?

Since you've just started, I'll just go over the first season. First off, I assume you've seen "Thirty Eight Minutes" where Sheppard had the bug on his beck? Moving past that...
Episode 5: Suspicion
One of the Athosians is suspected of being a spy for the Wraith. The Wraith do show up briefly, but I don't there were any
gross scenes featured. Unless the Wraith simply appearing counts as gross. It's mostly a
who's the spy story, and a good one at that.
Episode 6: Childhood's End
This one's a fun, independent story. Nothing gross that I can recall.
Episode 7: Poisoning the Well
This episode deals with Dr. Beckett helping a people develop a method to make them immune to being fed on by the Wraith. I don't want to say more, because it will spoil the plot. There is one scene that may or may not be gross. Just watch. It's not what you think, and you'll be asking yourself what just happened!
Episode 8: Underground
This episode introduces a potential ally who shifts back and forth between friend and foe depending on the episode. The Wraith do appear, but I can't remember if anyone was fed upon.
Episode 9: Home
Atlantis finally makes a connection to Earth, sending a few representatives home... or did they? This was a very special episode. It also stands as the only episode where Don S. Davis guest starred as General Hammond.
Episodes 10&11: The Storm / The Eye
The big, mid-season two-parter! Aside from people getting shot and one person's arm getting cut, nothing gross. You'd expect the big mid-season two-parter to be all about the Wraith, but the writers went an entirely different direction. For me, this was the show's best story prior to the final episodes (of the season).
Episode 12: The Defiant One
This one is a stand-alone episode, meaning it's not really followed up on. It deals with Sheppard and McKay pitted against an ancient Wraith. There is one, maybe two gross scenes. It's a highlight, because it shows just how dangerous the Wraith are, but it also shows just how resourceful Sheppard is.
Episode 13: Hot Zone
Every science-fiction show has to do an
outbreak episode, right? This one doesn't disappoint. The grossest thing you will see is a little blood out of someone's nose, or something like that.
Episode 14: Sanctuary
Nothing gross here, you'll love this episode. It's best if I say no more.
Episode 15: Before I Sleep
Remember the Time Jumper that SG-1 found? This episode explores it's origin!
Episode 16: The Brotherhood
I don't recall anything gross in this episode.
Episode 17: Letters from Pegasus
The Wraith are coming! This episode is a clip show and mostly features the characters making goodbye video diaries to their families and friends. Personally, I'd say you can skip this episode. However, it's worth seeing if you're really invested with the cast.
Episode 18: The Gift
This episode explores Teyla's ability to sense the Wraith. The episode is high on frights, but I don't recall anything gross being displayed.
Episodes 19&20: The Siege, Parts 1&2
It's the two-part season finale. The Wraith besiege Atlantis! Naturally, you're going to see some Wraith action, which means there's bound to be some gross scenes.
I hope this assessment helps. Oh, I almost forgot. If you're wondering when this season takes place in regards to SG-1, it's during that show's 8th season. "Rising" began after "New Order, Part 2," and the
Atlantis finale takes place right after SG-1's "Moebius, Part 2."