I recently updated the driver for my us1800 interface and now have latency issues when tracking guitars and vocals. I haven't messed with any of my previous settings because it used to work flawlessly using the input echo while tracking. Now, it's way off and I can't work with it. I have it set to ASIO / normal latency just like before. Now it's saying round trip latency is 30ms. The wave profiler is nowhere to be found. Any help would be appreciated. Thanks, Ken

The wave profiler has no effect on interfaces using the ASIO driver. Since you updated the driver you may need to launch the TASCAM supplied client application for your interface and adjust the setting there. SONAR cannot make adjustment to the ASIO driver.

The problem is only there when I activate input monitoring.......is there any way to monitor vocals or guitar without using this option while tracking? (through headphones)

Well there's no way you would have had no RTL in the past. My guess is it would have always been around 9ms at very very best. 20 - 27 ms is what I used to get with XP drivers. I get 9 to 12 ms now with W7 64 bit. I use the Normal setting too for stability reasons. Anything lower will crap out. 
The Tascam is over all a well made, good sounding interface with the only flaw being the drivers are not that great. So therefore it has always had pour performance in the round trip latency dept. 
You cannot use input echo, that's all, Use the blend knob and direct monitoring. Only thing you cannot do is try and listen to efx's or guitar rig in real time. So what. If this bothers you then you'll be paying a LOT more to get 3 to 5 ms of RTL.