Needing a good walk around lens

I'm in need of a good walk around lens, the thing is that I'm on a tight budget.. I've got $500 to spend tops... The lenses I have now are: Canon 50mm 1.8, 10-22mm, 55-250mm. I have the super wide angle end covered and the telephoto, but am in need of something in between. I would love the 17-55 2.8, but it's a bit too expensive for now... Here's what I've been looking at:

Canon 85mm 1.8 $400
Sigma 17-70mm 2.8-4 $470

I like to take pictures of all kinds of things, architecture, wildlife, potraits of my 1 year old which is why I'm interested in the 85mm 1.8. I'm just worried that 85mm will be too long... I'm interested in getting the Sigma because it covers a good walk around range, but I'm just not so convinced about the picture quality in comparison to the 85mm 1.8 from what I've seen in the threads... Any advice? Thanks.

with a $500 budget most will probably suggest tamron 17-50 non-vc

you could sell your kit lenses (18-135 & 18-55) and get it for next to nothing. or upgrade to the sigma 17-50 OS within budget limit

or get both tamron 17-50 non vc & canon 85 1.8 (after selling the 2 kit lenses). the 50 1.8 should cover your 1 year old though.

Tamron 17-50mm 2.8 non vc or the Sigma 17-70mm 2.8-4.0 OS. Both lenses are pretty well liked.

^^ +1 for the Tammy

Get a flash -it will make any lens you have better

The 85 1.8 won't make a good walkaround, way too long.

Either the tamron 17-50 non VC or the sigma 17-70 OS, or if you want a prime, the sigma 30 1.4 gives you a normal FOV on crop, so its a great walkaround lens too.

Tammy got a lot of happy user. And it is quite good for the lens in it's class.

I had some of your same lenses. I sold my 18-55 and my 18-135, and bought a 15-85.

85 is too long for walk-around and absolutely short for wildlife.
It is sharp portrait lens.

If you have 10-22,Tamron 28-75 2.8 will serve you well for walk-around and as very good portrait lens. It is less then 500$.
It is sharp wide open at 75 which is the ticket for nice looking portraits.

I had the Sigma 17-70 before I splurged fro the 24-70. The Sigma is a real good lens for the money. Pretty sharp and well behaved.

85mm is not a good walk around lens at all, way too long, more suitable for wildlife or portraits.

I suggest the tamron 17-50mm non vc version. I owned this lens before I bought my 24-70mm L, very nice lens indeed.

The Tamron 28-75 2.8 would be my choice. The 2 other options for the best walk around lens IMO is either the Sigma 17-50 OS or the Canon EFS 15-85 IS. You can get a new Sigma for around $650 or a refurbished 15-85 directly from Canon Online store for about the same price.

I have the 15-85 and it is my very first zoom lens upgrade from my kit 18-55. I traded a few lens over the past year or so but kept the 15-85 because it is outstanding. The IQ, range, USM ring, and the best Image stabilization I have ever use. Add a Flash for low light or just supplement it with your 50 1.8 and you should have it cover. The UWA range of 15 to the medium telephoto range of 85 cannot be beat if you are going to a one lens solution.

The 85 would not be a good walk-around on a crop camera; it's an awkward focal length, the kind of lens you put on the camera for a specific job but don't want to keep on there permanently. I'd recommend a nice f2.8 zoom. My own choice was the Tamron 28-75, which I find to be perfect for photographing my kid, and also for portraits. I've just done a series of animal portraits for a charity calendar, and used this lens for 75% of the pics. It's just wonderful. If 28 mm is not wide enough, many people like the Tamron 17-50, which is also constant f2.8. However, you already have a 10-22, and so the 28-75 would be my recommendation. You can find them used for around $300, but even new, it falls within your budget. It's a very sharp lens that will do a good job for you.

Are you unhappy with the picture quality you get from the 18-55IS? Mine is pretty good. If you want a general purpose lens that can do a good job in low light, consider a wider fast lens, like the 35f2 or 28f1.8. I get more use from the 35f2 than my other primes, and I also have the 50f1.4 and the 85f1.8.
The 85 is great for candids on a crop and the 50 is a good portrait lens, and short telephoto.
I often wind up using the 35f2 because it is versatile, sharp at f2 and AF is fast and accurate.

So maybe you are not really after a walk around? How big a factor was wanting the 85 1.8 for portraits of your son? If you really want that, I say do for it as 85 1.8 is really good, optically with bonus of very fast focusing.
Just walk around with your either 10-22, 50 1.8 or both.