In need of some new lighting!

My 220ex just isn't doing it anymore, its great for fill flash, its very helpful on camera when I've got reasonably good natural lighting to begin with. So I'm looking to upgrade soon and I'd like to get started with a basic strobist thing. I'll be getting an ABR800 within the next few months but in the meantime I'm looking for something cheaper and more portable.
Currently considering:

Sigma 500 DG Super
Sunpak 383 and wein optical slave
Sunpak 433 and wein optical slave

I'll be using whatever flash i get off camera triggered by my 220 on camera most often. Im leaning towards the sunpaks as they are cheaper, but if it would be enough of a benefit I'd suck up the cost of the sigma, are there any others i should be looking at? which flash would you all choose?

You know the 220EX's preflash would fool the optical slave, right?

Of course i would forget about that stupid preflash.

How about selling the 220ex and picking up a sunpak 433 for on camera use. And getting the sunpak 383 with optical slave unit to fire off camera?

I have a Sunpak 383, but don't know much about the 433. I look at B&H, there's a 433 AF for Canon, which is a TTL dedicated flash with no manual adjustment, don't know if it would work on the XT. Then there's a 433D, from what I can remember, the D is very similar to the 383.

I don't like to use my 383 as the on camera flash: 1) no focus assist, 2)limited auto flash setting choices (only 3 apertures).

Sorry keep throwing curl balls at you. If you looking for a 220EX replacement, I would take the Sigma out of those 3 listed.

Thanks for the input Lotto, i really appreciate it. The 383 is looking like quite a formidable little performer and the more i look around the more i think i may just be getting rid of the 220 in favor of two 383's and a optical slave unit. Having never used off camera flash im not entirely sure how this will all work out but i suppose having a 383 dialed down on camera and one at full power off camera could make for some nicely lit portraits. However your not the first person i've heard not liking the 383 on camera, is there another flash i should look at that i could have relatively cheap?

If you are planning on using the Sunpak 433AF off camera in true strobist style, then the 433AF type NE (Nikon) is a better choice as you can manually adjust power from full, 1/2, 1/4, 1/8, 1/16. Much more useful than the Canon type which only operates at full power in manual mode. I have one and it's a great flash.

Oh, also I have one of those Wein optical slave thingamabobs...they are a forty dollar piece of junk.

Sunpak 433AF Nikon