Check my sig topics, particularly Tarmak. (Before you start, you may also consider whether you want to learn any ergonomy mods and the Extend mode.)

For instance, for an ANSI keyboard you could do a Tarmak transition to A-Wing Curl(DbgHk) Colemak like this:
   

Again, that's described in my sig topics.

I second Amphetype as a great choice. I type-read books with it.

Yes, they are. The downside to them is technically you're moving more keys (although mentally it's a very minor upheaval!), but among the upsides are straight wrists (no ulnar deviation), better finger load balance (especially right-hand pinky), better access to AltGr/Back/Enter/RShift, better hand separation (felt in the shoulders). The Curl mod seems faster to me, as the DH and G keys are in better places requiring less effort. I'm faster with it, at least.

The Extend mode is the single best thing to learn next to Colemak itself, and can be used with QWERTY or whatever layout you wish so you could start using it today if you want.

The "little extra button" keyboard is the ISO/World keyboard; yours is probably ANSI/US (and no, that's not the only "standard" around!). There are plenty of solutions for that too. Most of the stuff here works for both, but the Angle (and by extension, Curl) mod is more natural on the ISO board. For ANSI, I'd go with A-Wing myself as on that image above (moving the brackets over to the left).

Support depends on what you mean. I use PKL for Windows and my own mappings for Linux/XKB; another user has made Mac implementations. Support's nearly as good as for vanilla Colemak, I'd say, except that vanilla Colemak comes out of the box for Linux now.

Whether it's better than standard Colemak? In this case it depends mostly on how you feel about the QWERTY G and H positions. Some think they're a bit hard to reach so they shouldn't be considered quite as superior as the other home positions. The creators of layouts such as Workman and Norman thought so. Their layouts aren't as good as Colemak if you ask me, but I've come around to their view on those positions. The Curl mods fix that by moving the more common D and H to positions on the bottom row that I consider better than their reputation. Just think about it, how you feel about the positions and how good they are relative to each other. Read up on my Curl thoughts (links from the Big Bag) if you wish.

simple question...for your angle mod..i'm reading through your site but maybe missed this...do your fingers still go to the home row after each stroke? or are you bringing the pinky up?

I have a mechanical ISO keyboard with US markings (from Unicomp) so it's possible to get hold of but not so easy. It's kind of a funny story about the extra key though: Microsoft designed the ISO keyboard because international users needed more keys (as many have special letters). But the US customers didn't like the thought of having to reach a little further for the left Shift so it didn't catch on there and we were stuck with two standards instead of one new one. I think the Enter key is better on ANSI though (but that's helped by the Wide mod so it's okay now).

PKL is a program written in the AHK language that many use to script windows hotkeys and stuff. It's really well written and I've made many files for it. So to use one of my PKL layouts you'd run the PKL program (it can run at startup so you don't have to worry about it).

The idea with these ergo mods is that although several keys change places physically your fingers will be hitting the same keys as before for the most part. The symbol keys that move are rare in use so they won't disrupt typing flow. Thus, ergo mods are really simple to learn although they may look daunting at first glance.

Oh, curses! I see now that I forgot to move the homing markers on that image. Yes, the starting position is at the same keys as before: ARST NEIO. That's a major point of this.

Try refreshing the page (Ctrl+F5), I've fixed the nubs now.

I'm working on releasing a Tarmak Colemak-Curl(DbgHk) progression for the A-Wing mod! Whether you use the Tarmak steps or not, that'll include A-Wing modded QWERTY and the full Colemak-Curl layout, with help images. Also, it'll enable the Extend mode so you might be interested in giving it a spin. My current PKL download (from the PKL Big Bag topic) already has several ANSI layouts so you could look at Extend whenever it pleases you, mind.

The Tarmak layouts don't have any AltGr remappings (or rather, they just pass through any such mappings or lack thereof that the active system layout has), but you ANSI people tend not to use those anyway. ;-)

ok I see a lot of your answers now. this is amazing.

i'm having a heck of a time getting this mod..i dl your whole package but can't figure out which one to run...do I have to modify one of them or something to get this one you recommend??

thanks in advance!

Ah ok...I thought I was going nuts not finding it.

Yes I think this is the way to go for me. I have to think about what to put on the spot for brackets...I'm thinking backspace for the lower one and making caps into ctrl. Hmm dunno about the top one yet...maybe "

Or maybe a / and make / into a ?

I think I use ? Much more than /

Anyway, can't wait

You don't want to lose the brackets completely though. Having multiple " and \ on your layout seems like a waste to me so maybe just put, say, tilde back in the corner, {} back where they were, [] somewhere. Use the AltGr/lv3–4 mappings maybe?

I started out my layout experience by moving symbol keys around like you're doing, but ended up with all of them in their standard US positions (apart from semicolon, obviously). I found it more valuable to stay compliant with a large part of the keyboard world than finding marginally better positions for some very rarely used keys. Also, that Back mapping may work well or not depending on your luck. As long as you still have the original Backspace I suppose it'll be fine though.

Interesting solution for an ANSI keyboard.  Are you not also going to have an Extend layer?  With that layout, I'd be tempted to try Extend where you have backspace (Qwerty A).
Also your number keys are offset from the home position relative to usual. Perhaps you might want to move them one space right also?

here's the latest

i still want to move the ] and [ to an extend layer as i dont ever use them. we'll see

image hosting

photo uploading

Sweet! What're your thoughts on moving the numbers over to the right one?

I'm thinking I'll want Backspace on that bottom bracket...we'll see how it feels...I just personally number use those things

With that pkl file can I just edit it myself to make a few changes? Or do I need to know how to program?