Your last point in your 1st thread click here was the reduction in speed due to one broadband connection shared between 2 computers.
You would only feel this if both computers were downloading large files at the same time.
For normal web surfing and emailing, you will not feel any difference.
Note that even the real-life data throughput of standard 802.11g wireless of 10-20 Mbps, is far in excess of broadband at 4 Mbps.
So file transfers within your own Local Area Network (LAN), be it wired or wireless, will be far greater then your internet access will be.
The best pre-N MIMO wireless networking speeds are probably around 50-70 Mbps.
Wired is typically 100 Mbps, sustained.
With special routers and LAN adapters, this goes up to 1,000 Mbps.
Just conveying the relativity of these things, to avoid giving you the wrong impression.
I am very satisfied with my pre-N MIMO Belkin router and unusually, non-Belkin (Linksys) pre-N adapters.
Not held back by the prospect of hard-wiring a network, its the flexibility of placement that I appreciate, as I am forever changing room layouts, etc!!
Hope that gives you a start on your quest!