How *best* to convert lps & tapes to digital files?

[Josef Lowder]

.
I've searched the 'net and read many articles on this subject, 
but I'm still not clear on what might be the *best* way to do this. 

Some have said that one can plug a turntable or cassette player 
directly into a mini "line-in" jack on a laptop computer and use
'audacity' to record, clean-up noise, edit tracks, and burn CDs.

Others have said that one must use (but be careful using) amplified 
output from a stereo amplifier or headphones output or through a 
mixer to a "line-in" jack on any computer sound card to do this. 

Also, saw link: http://www.vanemery.com/Linux/Rip/rip-analog.html

Today, my son pointed me to a nifty turntable that plugs directly into
a computer usb port to do this.  Investigating further, I found a small 
box called "ADS Instant Music RDX-150" for $39.95 that claims to allow 
plugging in a turntable, a cassette player, and other devices and 
then plugging that item into a USB port to convert analog music 
to digital MP3, WAV, WMA, and/or AAC files. 

It's available from here: 
http://www.meritline.com/ads-instant-music.html 

There seem to be several different brands and models of this item 
(i.e. from Tiger Direct and others) that do essentially the same thing, 
but I can't tell if there might be an important difference in the 
quality or capability of some of these items. 

So, before I order one of these, I thought I should ask my trusty 
PLUG friends for advice and wise counsel.