Hacienda pointed me towards this thread.
Clearly it depends upon your commute time. If you're getting to Salford Quays for 8am then most ways will be OK. Any later and things become more congested/trickier. It's generally more congested in the evenings regardless of time.
There's lots of good ways to get from Wilmslow to Salford Quays. Generally, don't head into the city centre and back out again as that's pointless (sorry Foss). I'd be wary of the airport tunnel way, simply because although there is a cycle path alongside it, the path is pretty poor after the tunnels end and it's better to go on the road. However, it's a 50 at this point and then there's a tricky set of lights and roundabout to negotiate a bit further on.
I'd initially go for Stanneylands, then past the airport, Thorley Lane to Timperley, get across the A56 somewhere near stretford and go past the Kelloggs factory.
I've drawn a route as much easier to describe it properly:
http://www.bikeroutetoaster.com/Course.aspx?course=513691
Note a couple of things:
-I've tried to put you as north along the A56 as much as possible. This road is pretty congested and I tend to avid it as much as possible, but you'll find your own personal tolerance and you might decide to head a more direct route to enter the A56 (all the way down Park Road for example).
-There's a cycle/footbridge at the BBC which you can enter via the Imperial War Museum car park and hence I have stopped the route at this point because clearly I don't know ehere your working.
Here's an alternative way to avoid the A56 altogether:
http://www.bikeroutetoaster.com/Course.aspx?course=513692
Also, you can cut through Sale Water Park to get to Chorlton which is a pleasant and quiet (and still fast enough) alternative.
There's also a very good canal path (wide and fast) that runs most of the way from Timperley to Salford Quays. I'm pretty sure (from people's strava rides) that there's a few BBC workers that commute down the canal path to the BBC offices/
Good luck with it and please do ask if needed.