I can only speak for myself, but I wouldn't be looking at the streak.
1. It looks like it's on AT&T, and I don't like them a whole lot. You might be able to ignore this point if you don't have a problem with them.
2. It's just too big. I wear cargo pants daily, but even with those I have a limit.
Some other things to consider. Are you the type of person who likes to always have the latest and greatest? If so, I'd recommend waiting. So far as I can tell, nobody knows for sure when the dual core phones will be out, but it's looking like over the next three months, or less, several should be available. The problem with this mentality is that it's always true. There is always something better coming out in just a few months, and there are distinct advantages to having a phone that's been out for a while. It just seems like we're right about to start a new phone cycle soon, and if nothing else, there will probably be more incentives for the streak when that happens.
Do you plan on leaving it stock or rooting? ROMs? I don't know how big the dev community is for Dell phones, but I would imagine it's larger for HTC, Motorolla, or Samsung.
Those are my thoughts, convoluted as they are. Personally, I'd wait at least till the end of January unless something spectacular comes out before then.
