What is the best voice recorder to record lectures in large halls?

I need to buy a voice recorder not more than $100.It should be small as i can keep it in my purse.And should be able to hear the lectur clearly even it is recorderd from 30 feets from the lecturer.[And i dont like to keep the recorder on the table so i am keeping it inside my bag while recording.]And recodings must be able to take to my PC.And it must can record about 20 hours,can be recharged like mobiles.Its better if it has a USB hub.Is there any recorder with these capabilities.