[LAU] looking for a USB soundcard

Hi Linux Audio Users, I am looking for a "USB soundcard" (if that has a meaning at all). Here are my needs: I want to record myself. I want 24 bits / 44.1KHz. I want a basic device with one stereo input plug (minijack or RCA) and one USB output (fast enough to send audio digital data to the comupter in realtime). I have the recording gear. All I need is an electronic piece of hardware that would pick up analogical audio signal and send digital signal to the USB input of my computer. It should be as simple as possible. I don't care about effects, more than stereo stuff, blinking lights or whatever. Just a box with one (two if RCA) plugs and the USB connector and so be it. It should preferably work with basic linux distro (ubuntu preferred) with no configuration at all. I plug the thing in the USB port and ALSA sees a new input device (whatever that means, I don't know much about ALSA but I'll learn; I don't want to bother with something else than ALSA like JACK, it's already painful enough, OSS come back! open("/dev/dsp") was perfect... (yes I'm old and lazy)). Do you know any hardware that does that? or that is close to that? (I can compile a new kernel, install drivers, and so on, it's just that with age come laziness.) I of course would prefer something that does not add too much noise to the audio signal. Well, just like any musician I guess... I can relax my needs. 16 bits if 24 bits is not possible, 48KHz if 44.1KHz is not common anymore and so on. (What? yeah I come from the past.) By the way, does 24 bits add a lot of comfort when it is about recording music? By the past I struggled hard to avoid saturation with my old 16 bits soundcard, that's why I wonder if 24 bits is better, a lot better, a little better or not better at all. Thanks for your help / suggestions, and happy music, Cédric.