The Clip+ sounds better than the J3 without any sound enhancements of equilization. If you are into sound enhancements though, the J3 offers more options. The J3 has around 50 hours of battery life vs around 12 or so for the Clip+ playing mp3 files.I sugget you get a 2GB Clip+. It is just $30 on Amazon. Add a cheap 16GB($10) or 32GB($25) micro SDHC card to it. If you need more than 12 hours of battery life, then get a usb battery pack.
The Tekkeon mp1580 usb battery pack is nice since it takes nimh AA batteries and is only around $15(plus you need to add 4 nimh AA batteries).
There are also smaller lighter more compack lion battery based usb battery packs.
The Duracell MyGrid usb charger looks interesting(you don't need to use the mygrid system).
The MyGrid holds around 6,700 mwh vs around 13,000 mwh when using 4 Sanyo 2700mah AA nimh batteries in the Tekkeon mp1580. The MyGrid is much smaller and much lighter. I guess the MyGrid isn't much larger than the tiny Clip+. I guess the My grid is probably good for around 4 full charges of the Clip+ battery, while the Tekkeon mp1580 might give up to around 7 full charges(before you would need to swap the batteries in it or charge it).