Of course the majority in this forum is into STFs, and so am I. In my opinion, LS&Co's 501 STFs are the only original jeans. They started it all. It's really amazing how this great product survived essentially unchange over such a long period of time.
However, I do like jeans/denim in general and do like other styles and brands, too. For me, jeans have always been an American product. Therefore, I prefer the Big Three (Levi's, Lee, Wrangler). Coming to think of it, I do not own any other brands except one pair of Guess jeans (I'm still looking for the screen accurate version of Back to the Future) and two custom made jeans. I am not interested in other brands, but that doesn't mean there aren't other jeans that couldn't tempt me.
I love rigid jeans. The look is classic, and it fascinates me when looking at a pair of faded jeans to think of how differently they looked when they were new and starchy. Every now and then I take all my pairs out of the closet and inspect them. I love stonewashed jeans, too. From a purist's point of view this may be despicable, but that's the way I am. As long as they finish has an even wash (no artifical whiskers and stuff). I grew up with them and loved them, there were no dark indigo washes available in the late 80ies/early 90ies in Austria.
I'm not very much into "coloured" (twill) jeans. Jeans are blue to me, the twill version simply don't have the look. There are/were coloured denim jeans (the new STFs, for example), but as I said, jeans are blue.
There are the Vintage lines, each of the Big Three has them. I once had the 1901 501XX model. But when talking about jeans I usually have styles in mind which the average Joe can afford.
Fit-wise, a regular fit suits my body most. This would be 505 or 13MWZ territory. I don't know the "new" 505s, I heard they are too baggy. I only know the 90ies/late 80ies cut (slightly tapered), they fit me well. I had a look at the Lee regular fit jeans, they are reasonably priced and the fit looks good to me. What I like about them (as well as Wrangler's Cowboy Cut jeans) are the high back pockets. Who wants the back pocket on the thigh? That's a downside of Levi's 505s, the pockets are way too low.
The '93 501 model has a great fit for me. The leg opening isn't too big, this model has a slight taper. The new ones are straight.
13MWZs are good, the thigh could be a little slimmer. A perfect fit for my body could be a mixture of them with the 936DEN slim fit style. Wrangler's indigo color doesn't look as "classy" as LS&Co's and the broken twill denim weave doesn't have the classic denim look, these are slight downsides for me. What I do like are the colored jeans from this style, here the bwoken twill weave does it for me.
I haven't tried Wrangler Rugged Wear jeans, but their regular fit style might be worth a try.
One thing that bothers me a lot recently are labels, trademarks and such stuff. When looking at clothes I almost get the feeling of looking at advertisments. So on some jeans I do remove them, this works well on rigid jeans as there will be no sign there was something sewn onto them after one or two washings. I quite like the look of "naked" back pockets, too, so sometimes I remove the stitching. Of course I do have unaltered jeans as well, I just like variety.