Tarp.
Helps to have under the tent, especially if it's a wet day.
Also standard camping supplies, like emergency first aid kit, sleeping bags, flashlights/lantern, pocket knife and possibly a full sized knife, a portable butane hot plate (if you plan on cooking for yourself and don't want to build a fire).
This, only it is more for the day after a wet day. The plastic / tarp under your tent will stop the moisture from the ground going up into your tent.
Also face the opening of your tent downhill. If it rains real hard the water will run down the hill and into your tent if it is facing the wrong way.
Pick any bug spray with DEET in it (closer to 99% the better, however its not really good for you - it WILL keep the bugs away). At least some deet at a minimum.
Bring something to put in your car in case your coolers get muddy. You dont want to just put muddy coolers into your car when it starts pouring. Cover an area with plastic / tarp specifically for this in your car for things you want to keep dry in the event of a storm.
Get a double high air mattress. When they lose air you get closer to the ground. Double-high keeps you off the ground longer - and usually long enough to put air in it the next day. All air mattresses lose air regardless of what you buy. Other options are cots.
Your crap will get dirty in the tent, just a nature of the beast. Keep this in mind when you pick what you take. Having a place to wipe your feet off is good for the morning when you head to the showers.
Buy a few gallon water holder to use to wash your hands / dishes / whatever at the camp site.
That is about all I can think of. I camp a lot myself, try to make sure I do it once or twice a year. BTW, I have Eureka tents but I haven't bought one in years, they have lasted me forever. As to the current quality of products on the shelves, I couldn't tell you.