Yea...too little information here. SO many questions...
Do you need it for anything? If no, then okay be aggressive.
If you have plans within 5 years for it, consider a balanced fund.
If it is less than 5 years, consider bonds or CD's even
And then that all depends on the plans...are they really important or are they just fun and could be deferred?
I re-read your post and I suspect you are having a timing issue. I'll bet you are seeing the market as up, and about to crash. I think we all are--and yet we could all be wrong. Honestly I think it's a comfort thing. If you got some guts, then go ahead and throw it all in. If this market just seems too insane to you then there is nothing wrong with doing 5k or even 10k at a time. You're still investing at a good rate with DCA. You could win or lose that way but it sure won't be dramatic. Again, this might all depend on the "need' of the money.
For example, if I thought I would need it soon DCA would be more attractive. If I thought I don't really need the money at all or I just might want to go on a cruise some day then maybe I would throw it all in. But I must admit, throwing it all in with the market this high would be hard for me.
And to answer your question more directly: I would probably do something like buy a house with cash or payoff a mortgage. I know it doesn't make financial sense around here but I love the idea of having a house paid off. Maybe you already do or maybe you would too.