[jankowsky]

Need to feed internet cable through existing wall from basement to upper level

[Stratmando]

I like concealed, best as possible, affordable, look for inside walls of closets or the back sid of intended wall, always look for access above and below as well.
Can you describe walls(block?), attic? basement/crawl space.
Also see how other things go from basement and up(plumbing, duct work, electrical)

[KISS]

Home Depot now carries flex steerable drill bits. These are about 4' long. Once you detect where the studs are to avoid them with a stud detector, you can cut a hole for a low voltage ring. This rig will help to protect the edges. A 7/8" hole will be very difficult to drill, but it's very useful.

Depending on the size of the bit you get, you may need a variable speed reverseable 1/2" drill for the power that you need or you can rent one.

Once you determine nothing is in the way, you drill through the hole that you made with the ring on with the steering wheel.

The big drill bit has a hole in the end that you can thread pulling string into and pull the string through the hole the other way. When you fish the wire, also fish some pulling string too for the next thing you need to fish.

For really long and impossible fishing you can use a low voltage corrogated tubing from both ends. Conduits & Raceways - HomeTech Solutions

I like the 2 gang boxes because of the ease to put hands in the wall, etc. These may be difficult to find. The Leviton dual wall plates with inserts work OK, but wall plates that divert the ethernet cable downwards is usually better, but I don't know where to get them.

That's not the only way, but it is a way from the basement to the floor above when you have access from below.

[Scleros]

A typical install starts with finding a clear path from basement to upper floor. The shortest distance is not always the easiest or fastest. Potential obstructions within a common wall include blocking, HVAC ducts, plumbing, and electrical. Running the cable beside an existing plumbing run can reduce effort. Electrical runs can be followed too, however CAT5 or better cable needs to be shielded or put in conduit when run close to electrical wiring. Otherwise, once a clear path has been determined through the use of a stud sensor or exploratory drilling, the top and bottom plates of the wall are drilled from basement and attic, and the cable(s) run. A length of corrugated plastic tubing can be installed to facilitate future cable runs. Once the cable is run to where it needs to go, it is terminated to a wall jack port mounted in a retrofit wall box or a surface mount box. Surface mount conduit can also be installed to transition from the wall to closer to where the port is to be used.

My install kit for UTP cable:
Tool Belt
Flashlight - For looking into walls.
Headlamp - For working hands free in attic or other unlit locations.
Cordless Drill - For powering drill bits.
Installer Drill Bits - For drilling deep small holes.
Auger Drill Bits - For drilling larger holes.
Fish Tape - For pulling cable.
Stud Sensor - For finding wall blocking.
6" Diagonal Pliers - For cutting cable.
Cable Stripper - For preparing cable for termination.
Punchdown Tool - For terminating cable on wall jacks.
Cable Tester - For verifying cable continuity, punchdown.
LAN Tone & Probe - For figuring out which cable is which.
Cable Hangers - For supporting cable on horizontal runs.
Solid CAT5E Bulk Cable - PVC or plenum jacket determined by installation environment.
Jacks
Wall Plates
Cordless Screwdriver - For wall plate screws.
Retrofit Electrical Box (local home center)
Wire Ties (local home center)
Velcro Cable Wraps (local home center)
Drywall Screws (local home center) - For mounting cable hangers.
Hollow Wall Anchors (local home center) - For mounting cable hangers.
Surface Mount Conduit and Termination Products.

Kit for coax cable almost identical except for different stripping, termination, and cable support tools.

[Scleros]

...but wall plates that divert the ethernet cable downwards is usually better, but I don't know where to get them.

CablesToGo has 45 degree plates in small quantities. Other vendors, Panduit, Seimens, etc. also have them, just have the hassle of jumping through their distributor hoops.

[KISS]

BTW - 6" is the recommended distance from electrical when running parallel. OK to cross.

[KISS]

Recommend something like these for drilling holes:

Piranhabits Flexible Fish Bits available from Lashen Electronics

With the steering guide

[Stratmando]

Here is another company for fishing wires:
Labor Saving Devices
Nice stuff, Lashen has much of the same.
If you have recessed cans(6" provides more room than the 4" easily)
Remove the 3 or 4 screws and push can up for light if room in ceiling, or pull down, then Use a Camera or Cell phone camera and take pictures in different directions in ceiling to find a clear path.
Here is a cool tool for looking inside the wall:
http://www.lsdinc.com/content/product_details/33