Here are the stethoscopes I like and recommend:
1) Littmann Classic II S.E. (Excellent fit and finish, great acoustics, plus it has a bell which you may need for school)
2) Littmann Master Classic II (one-sided chest piece, great build quality and acoustics)
3) ADC 603 (Like the Litty Classic II S.E., but cheaper. Feels good, works very well, sturdy)
4) MDF One, Model 777 (another standard scope like Littmann, but less costly, free parts for life, comfortable)
5) MDF Pulse Time Model 740 (I may get crap for this but here's my reasoning): MDF makes pretty good stuff, has a parts for life program, and this scope has a built-in, silent LCD clock with a second hand that makes taking pulses and respiration rates pretty convenient. It's light weight, and has pretty decent acoustics, though not like the others listed. It also came with additional ear tips and a spare diaphragm. I like it for basic assessments, and you don't have to worry about forgetting your watch! At first I thought it was gimmicky, but in practice it's very handy to use, FWIW. No bell though, if that's an issue for your school.
6) Welch Allyn Tycos Professional (sturdy, quality scope with a good warranty).
Things to look for:
1) Materials chest piece are made from. Stainless steel has the best sound transmission. Aluminum and zinc are pretty good, but their main advantage is light weight.
2) Tubing. I don't mind a double tube like the Sprague Rappaport, but I see the value in having as little noise artifacts as possible when learning to auscultate. With practice a Sprague can be a fine scope to use. But a single tube with a 'y' yoke may be best.
3) How do the ear tips fit YOUR ears? This is where one should try before they buy. I know people who love their Littmann and how it fits their ears (me for example), while others can't stand them. The tips need to seal out extraneous noise, and to do so, they need to seal your ear canals. Any good uniform shop will let you try out various scopes. DO IT! Stethoscopes are very personal things. Buy one (or two), put a name tag on it or otherwise mark it as your own, and then always keep it in site!
Let us all know how you make out!