I'd go with the 70th - Tolkien's illustrations fit the story better (imo), & have more of a 'fairy story' feel. Lee's illustrations are too 'realistic'.
Actually, I'd go for a nice Allen & Unwin edition (eg
http://www.abebooks.co.uk/servlet/Bo...%26tn%3Dhobbit ) for a number of reasons - 1) a nice older edition also emphasises the fairy tale feel - there's something 'magical' about old books 2) the A&U editions were much better quality than the current Harper Collins editions & 3), if you buy a second hand book you aren't giving any money to Rupert Murdoch.