Your 3G speed is your 3G speed. The modem on some phones is better than others but I have not noticed any real difference in speed on my wife's OG Droid to my DX to my buddy's D3 (I'm assuming the D3 I'm getting Tuesday will be the same). Run an app called Speedtest (available in the market) or you can go to
Speedtest.net to see what is faster. I will say that good Verizon 3G is faster than regular DSL. Not sure what you are using but it might be your router, I'd run that test on your home computer that is actually wired into the router, not wifi and see if it is markedly faster. I mean it will be faster but if you are getting like 1.0mbps down on wifi and 20mpbs down on wired... it could be the router. Also realize that the network load on the 3G is going to be different at different times. I can see over 2mbps down very late at night or early in the morning but have trouble hitting 500kbps down during work hours or in the evening.
Your best bet would probably be to upgrade your home internet to something that does not suck if available. As crappy as cable modems can be, they are still more than fine for streaming movies. I usually see 15-20mbps down on my Crapcast cable modem. If you happen to have access to FiOS, you should be on the phone with them yesterday to get it installed as it is simply ridiculous as far as speeds go. I'd hit 4-5mpbs on actual downloads and ping over 40mbps consistantly. LTE is actually very similar, I've seen LTE speeds in NYC and Philly over 30mpbs, it will be a problem if you are using it for a home network to watch movies and do not have a grandfathered unlimited data plan though as you can blow through even 12gb in a few hours on LTE no problem.