Thanks to netpanel for this download speed reference table:

http://www.netpanel.com/features/internet/times.htm

Find your Internet connection speed along the left-hand side, and the approximate file size along the top. The connection speeds are referred to in bps(bits per second), Kbps (kilobits per second), and Mbps (megabits per second), where applicable.

Don't confuse these bit per second rates with bytes per second. For example, a connection speed of 28.8 Kbps would actually download at a rate of 3.5 kilobytes per second in theory, not 28.8 kilobytes per second.

Also realize that the times shown in this table are only the theoretical download times. There are many other factors that can affect your rate of download. Keeping this in mind, you may want to use a little discretion when determining a download time.

Connection
speed
File size
100K 500K 1 MB 1.5 MB 2 MB 5 MB
9600 bps
9.6 Kbps
1 min.
25 sec.
7 min.
7 sec.
14 min.
13 sec.
21 min.
20 sec.
28 min.
27 sec.
71 min.
7 sec.
14400 bps
14.4 Kbps
57 sec. 4 min.
44 sec.
9 min.
29 sec.
14 min.
13 sec.
18 min.
58 sec.
47 min.
24 sec.
28800 bps
28.8 Kbps
28 sec. 2 min.
22 sec.
4 min.
44 sec.
7 min.
7 sec.
9 min.
29 sec.
23 min.
42 sec.
33600 bps
33.6 Kbps
24 sec. 2 min.
2 sec.
4 min.
4 sec.
6 min.
6 sec.
8 min.
8 sec.
20 min.
19 sec.
56000 bps
56 Kbps
15 sec. 1 min.
13 sec.
2 min.
27 sec.
3 min.
39 sec.
4 min.
53 sec.
12 min.
11 sec.
128 Kbps
(ISDN)
6 sec. 32 sec. 1 min.
4 sec.
1 min.
36 sec.
2 min.
8 sec.
5 min.
20 sec.
1.5 Mbps
(T1)
<1 sec. 3 sec. 5 sec. 8 sec. 11 sec. 27 sec.
45 Mbps
(T3)
<1 sec. <1 sec. <1 sec. <1 sec. <1 sec. 1 sec.

The times presented in this table are faster than they would be in real-world situations. The reason for this is simple: there are always delays between your modem and the targeted server. Even if you have a 28.8 modem, you'll likely receive slower performance. In some cases, you may only be getting 14.4 performance.