To answer this question, I actually prefer a plastic (poly) paddle. Better than wood OR stainless, and really cheap. your LHBS should have one (btw, if you're new here, LHBS = Local Home Brew Store, and most of us recommend you get to be on good terms with the owners
).
As for what everyone else said:
1) Carboys. I know many people here don't like them. I love them. I have 3, and use them all the time. They're easy to clean (provided you have a good carboy brush, or, as I prefer, one of the cleaners that attach to a hand drill), and they don't scratch easily . . . they also also allow you to see what's going on in your brew. I also use plastic buckets, which are cheaper, and work wonderfully. It's your call.
2) As I think was clarified, you can very easily use a 5 gallon pot for doing 5 gallon batches by simply boiling only 3-4 gallons, and adding the rest as top water. HOWEVER, I will note that MidWest is NOT cheap on shipping . . . SO, if you DO have a LHBS near you, you MIGHT want to price some of these items separately, and find out what it will cost to ship. I have found that, purchased separately, I can buy a 7.5 gallon pot at my LHBS or Kitchen Supply Store for the cost of the 5 gallon pot on MidWest . . . but the kit might be cheaper.
3) One-Step is a Sanitizer? I didn't know that. Honestly, I've always seen it billed as a cleanser. That being said, you probably STILL want to invest in some iodophor or Star San . . . they work better than just about anything else, IMO. Everyone on here seems to swear by Star San . . . but I use iodophor. neither is terribly expensive, and can usually be purchased at your LHBS as cheap as any online market.
If you're really looking to save $$ and get into this thing cheap, which I'm sure your wife would prefer (MINE DID!!), it is very east to go down to your LHBS and get a pair of buckets (at least one for bottling and one for fermenting - secondary isn't required), a 5 - 7.5 gallon pot (I use an aluminum turkey frier, though I do say if you use aluminum, you can't use it for anything EXCEPT your brewing), and everything else in that kit, except the carboys, and you'd probably save about $50, after the cost of shipping is added to the bill.
In the end, this is a great kit and a good way to start a fun hobby. Let us know what you decide, and what beer you brew first!!!