As anything but a juvenile I wouldn't think so. Not to sound all tang-policey on ya.

I would use what your wife wants as leverage to get a 6 foot tank =)

i hate my 90 truth be told i hate all tanks 24" in height its a pita to reach down to the bottom ideally my tank would be 20" high.a
blue tang would be ok as a juvie but it will quickly out grow a 70 or a 90g.they become rather big fish and need lots of swimming room.if you do get one get one as a babie but it will need to be passed on as it gets bigger:)

Thanks for the info on the tang, that is what I thought. No room for anything bigger than a 75 or 90 so will Need to pick between the two. If I buy new is perfecto a decent quality tank. Their over flow includes the plumbing or is aqueon better? I like the corner flow better on the perfecto compared to the offset on the aqueon. Thanks for the info.

Not a huge difference, but I like perfecto cause I have one Haha. If you want tangs but your biggest choice is 90 Do a 6 foot 90 with less rock work. That might suffice for a tang possibly

That's gonna be a pretty skinny tank. I'm thinking skip the blue tang until you can squeeze a 180 into your house :)
The 75/90 can be considered the same for tangs, both are the same footprint. The extra height won't matter either way. There are a few tangs that you could get away with, just do a bit of research on full adult size and aggression.

I hate that my 75 gallons is 23" tall...I can hardly reach the bottom so I wish it was longer and less deep. You do need a stronger light after 23", so you would need 400watt of MH instead of 250 watt.

I would not have anything deeper. Longer yes but not deeper. Each time I clean my glass I swear and swear because I hurt my arm trying to reach the very bottom to clean it. Can't use a magnet because the sand might get cought it in. I just wish it was like 2" less deep.

My 100 is 22 and I hate getting mysleeves wet lol I think 18-20 high is perfect

There's no denying you'll get more light to the bottom with 400 vs 250 w but that depends on a few things (some 250w bulbs destroy some 400 in terms of PAR). I'm running 20k 250w bulbs (much less PAR than your average 10 -14k) in a 27" deep tank and have sps growing (colorfully) on the bottom.

Brad's point is still true tho. I'd go with the 75 as well. It's a nicely proportioned tank. Before I went any taller in that tank size class I'd definitely go longer or wider.

really? what type of SPS?

I would not put any SPS at the bottom in mine and I have a Pheonix 14k in 23" deep.

I put them there at the begining for acclimatation but to get them in good color they need more light or they will brown out of be dull.

So I am wondering what type of SPS you grow "colorfully" at the bottom of a 27" deep tank running low par 20k 250 watt light?

Since this is relevant to choosing between the tanks... here is one of several. Tank's 36" wide to boot with halides only down the center:

http://www.fishbrains.net/images/404/transfer6.jpg