if you have to get a DP then the one you want to get is the DP95. It is the best of the bunch and the most rigid. The DP's after this and the Rubies really are only good for practice buckets. I have however seen some really good looking DP95's.
i've got a DP '96 and i think it's pretty good. i don't know if i just got a good one or what, but mine has a really good shape. nice flair, quite rigid. you can get a '96 on ebay for around 50-60, the '95 is gonna run you 100+. if it's a price issue, the '96 is totally worth it.
GCN is right, no plastic DP has a full visor. 95 is the best. You can find them as low as $50, but they can also fetch over $100. 96 is also good but make sure you get the one with the white interior. I thnik they made some with the green plastic and my understanding is that it is not as rigid. WARNING: I just bought a 95 for $60 and it is taking a LOT of work to make it right - actually it will never really be right. The ears need to be fixed, it is smaller so the normal decals and such don't work. I have to go DP because I am making this for my son, and needed a smaller helmet.
If you are making one for yourself I would buy one from one of the members here. Sarge is selling some right now that are not much more than a 95 DP and would be a MUCH better base to work from. If money is the issue and you have plenty of time, then 96 DP might be the best bet for you. Make sure you prime the DP's before painting or the paint will not set. And, again GCN is right, DO NOT leave it in the sun, it will get very soft and squishy.