(Which i am guessing you are) This year the max allowable contribution to both Traditional and Roth IRA's was raised from $4000 to $5000. If you are older than 50, you are allowed an extra $1000 as a "catch-up" contribution, making the total $6,000.
I think the main gist of your question comes down to the idea of
"The Time Value of Money". www.fincalc.com has several financial calculators that can help you answer many of the questions you are pondering.
Trof raised a good point about Preferred Shares. There are some excellent opportunities available these days with this type of security, with Triple-A rated issues yielding 7% and higher. One should take some time to learn about these securities before investing (obviously) as there are several different types that have varying characteristics that are important to bear in mind. They share many of the characteristics of a stock as well as a bond, but typically with a "Par" value of $25.00 Most bonds are issued with a Par of $1000.00 One primary difference between preferreds and bonds is that many are issued with essentially a perpetual maturity. In other words, most bonds have a specific maturity date - say ten years (or as long as 30, as is the case with a 30 year Treasury) but there are many preferreds available that have a maturity date in the year 2100. I have seen them as far out as 125 years making it unlikely that a purchaser will ever actually receive redemption at maturity and making "Yield to Maturity" quotes somewhat irrelevant. They are issued with a specific "coupon" rate but the actual yield fluctuates with the share price, just like a bond. They will trade around the $25.00 mark but there is no restriction so you could buy a preferred for $18.00 or even lower. As a general rule, the higher rated an issue is, the closer to par it will trade. Prices bid down as low as $18.00 usually reflect the traders having concerns about the issuer. A cheaper price means a higher yield. Be careful and verify the credit rating of the issuer and don't get too greedy. A 15% yield is generally not sustainable. There are plenty available however currently priced in the $20 - $24 range with coupons at 7% and better yielding upward of 8%. If an investor is interested in them, purchasing them below par (at a discount) is almost always a better idea than purchasing them at a premium.
One other thing to watch for with them is a "Call" provision. Most are issued with some sort of Call provision attached. You might not want to buy a share in January that could be called away in June,
unless it was a a decent discount and the call likelihood was high. For the most part, just as with Bonds, you want at least a year of Call protection so that you are able to collect a full cycle of interest payments.
Preferreds are considered "Fixed Income" instruments and warrant consideration as part of a well rounded portfolio. They tend to fit a particular sleeve of the F/I portion rather well. As with any investment, it is important to fully understand the risks involved before making a purchase.
I did some searching and found
this website which requires registration but no subscription fee. They have some excellent resources on Preferreds. You can also find listings of quotes and yields in a copy of Barron's magazine. You can find Barron's at any decent magazine rack. Both Barnes & Noble and Borders carry it but it is a weekly, so use the quotes as a rough guide only. Seems to me the WSJ used to print Preferreds every day but they don't any more.