I’ll stake my claim to Nike. Consider the following:
-Other than shoes for work, I have only owned Nikes since 3rd grade.
-I still have the first pair of Air Jordans that came out (not that they fit, but they are still around.)
8 pairs of Nikes sit in my closet.
-One of the criteria in my choosing where to play college basketball was based on who had a shoe/clothing contract with them.
-Due to the above choice, I have loads of clothes that bear the Nike logo. Shirts, shoes, hats, socks. I have a Nike robe. The best part is that a large majority of these items were free, because once a player that got free goodies while playing, you can always go back to the watering hole and get a few more drinks, regardless of how many years it has been since you played.
-My favorite basketball player of all time was also sponsored by Nike.
My workplace is guarded by Pinkerton. I know several of the Pinkers, and they all drink Mountain Dew. With that boring job, they need the caffeine. I have razzed them, saying they ought to wear MD patches on their uniforms as part of an endorsement deal.
Presenting the fully enigmatic R. R. Barrett, brought to you live and in color through the collaborative efforts of the good people at Fender, (We Make History) Mr. Pibb, (Put it in yer head) Macoroni and Cheese (It’s the cheesiest) and of course, by our friends at Trojan condoms. (No slogan necessary).
I can’t believe no-one has asked the Straightdope to sponsor them - think of it - a free mug 
I would be sponsored by…
Dr. Pepper Corp. - For my long patronage
Pepsi Corporation - Just because I gotta nab the big name corps. Not to mention I nearly paid the paycheck of at least one employee throughout each year of high school. (Latin IV first period requires morning caffeine).
TechTV - World’s biggest geek is a proud title I currently hold, and no you cannot battle me for it until the next battle in 2020 (original competition held in high school in 2000)
Slashdot.com - See above
ILM - George Lucas owes me a couple of favors.
Introducing the new Sublight! Powered by Starbucks.
Come to think of it, I already do have corporate sponsorship. Williams Communications gave me a free week at a luxury hotel in Waikiki for a conference, and now I carry my free Williams backpack with me where ever I go.
I am already a product placement for Leinenkugel’s, so they’d be wise to sponsor me, lest I begin to prophesy on behalf of another brewery.
- Gennessee Cream Ale, aka “Genny Cream”, 'cause I was practically weaned on it and 41 years later I still love it. Besides, it’s hard to find here in Arizona, so this way I could insure a steady supply.
- Drambuie, because it’s ssoooooooo good.
- Zippo, an icon of American cool.
- Finally, I’d let the major cigarette companies have a bidding war over me.
Since my sponsorship choices would appall nearly everybody, I’d dress in black (like I don’t already!) and called myself “Sinner”. 
RC Cola. Ive been drinking a 12 pack a week for over a decade.
Tang. A quart a day since I was 5.
Discovery Channel. Why else have cable, but for the smart, cool, creepy, fun stuff on the Disc Channels?
I’d have to go with Omaha Steaks, Miller Beer and Barbasol Thick and Rich Shaving Cream.
And what the hell, toss Gucci, Lincoln-Mercury and Circuit City on there too.
stv
I think Amazon.com and Old Navy owe me some sponsorship. I’m a walking advertisement for both, or as I often say, “I am Old Navy’s Bitch.”
Diet Pepsi is a close runner-up, and perhaps also the estate of J.R.R. Tolkien.
Well, I’ll go for **Coke, Starbucks, **and Saturn, since I’m a good patron, and J. Jill, Nordstrom, and Tiffany & Co. in hopes of getting sample goods. Oh, and **Clarks **shoes, too. And maybe a few local restaurants. Yeah, that’ll work. With any luck, I won’t have to spend much of my own money for the rest of my life. 
Rue, I’ll indian leg wrestle you for Lowes. Be forewarned, their help staff ask me where to find stuff.
In lieu of an Elvis jumpsuit, I’ll be a walking billboard for Lowes, Dr. Pepper and Franciscan Vineyards.