Auction ads is far more than eBay affiliate. They convert it to look similar to Adsense, with little thumbnails next to it. You always see in context ads for products on your web page. Its a great system, but IMO not worth it unless you have a large bit of highly targeted traffic.. At which point its a goldmine. If you want a type of system to pay you regardless of how well traffic converts, or how much traffic clicks on your ads, check out a CPM network - see my sig.
I love CJ. It took over 6 months to really see results. Plus being an investor, it's nice to see the company trade on a major stock exchange. Value Click owns 'em (Symbol: VCLK) But like everyone above mentioned, try out a few programs and look to match affiliates with your interests. That way, you won't get sick of promoting products you cannot relate with.
Spamming may give better and faster results to some people but I always believe that slow and steady wins the race.
Try the Gilletts Jeweller Affiliate program - it pays only 5% commission but the wait til you get your commission from sales worth $1k. Also the Bidz affiliate program has a distinct appeal to those looking for online bargains.
GoldenCan is a cool affiliate "aggregator," that makes it easy to include an entire affiliate store on your site, covering dozens of different merchants, with just a few lines of php code. I use them to power my affiliate store on my anniversary gift website (see sig). You still have to sign-up for the affiliate programs through CJ, Share-a-Sale, LinkShare, Amazon, or Performics, however. Paul